THE PROFESSIONAL MAGAZINE FOR ELECTRONICS AND …

THE PROFESSIONAL MAGAZINE FOR ELECTRONICS AND COMPUTER SERVICING

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VCR problems

Testing microprocessors using an oscilloscope

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Contents

f0.5A

1

RISE TIME PULSE WIDTH FALL TIME(HALF AMPLITUDE DURATION)

page 6

FEATURES -6 Oscilloscope update:

An oscilloscope refresherBy The ES&T StaffWhen the first oscilloscope wasconceived and built, the world ofelectronics changed forever. Theevolution, attributes, and uses ofthis vital piece of test equipment arefocused on in this feature article.

14 Testing microprocessors usingan oscilloscopeBy The ES&T StaffMicroprocessors, now being usedto control every kind of consumer -electronics product from TVs tomicrowave ovens, are sometimesthought of by technicians as com-puters and as difficult to service.Knowing how to approach them,however, can make servicing a lotless fearsome.

18 VCR system control problemsBy Arthur FlavellSYSCON problems-what arethey and how can a technician trou-bleshoot them?

21 The Best Idea contestBy The ES&T StaffEvery year the NPEC attendeeshave a meeting, titled the "Best Idea

page 56

Contest," at which they share ideaswith each other for improving theoperation of their service centers.These ideas have generously beenshared with ES&T readers.

ADVERTISINGSUPPLEMENT42 Distributors' showcase

When a technician completes adiagnosis and determines the causeof a problem in an electronics prod-uct, often that leads to the difficulttask of locating a replacement partthat will restore it to proper opera-tion. Obscure products from hard -to -find manufacturers are increas-ingly likely to be brought in forservice, and locating service infor-mation and parts may require detec-tive ability and tenacity. This annu-al showcase is designed to aid you,the ES&T reader, decide which dis-tributor is right to help you in find-ing the parts and information youneed to get the job done.

DEPARTMENTS2 Editorial

4 News

GIRomenie 23 Test Your ElectronicsServicing echnologv Knowledge

Volume 14, No. 4 April 1994

24 What Do You Know AboutElectronicsServo systems

41 Literature

53 Books

54 Business CornerWill Total Quality Managementwork for you?-Part 7

56 Audio CornerAudio and commercialsound servicing

59 Computer CornerSources for monitor schematicsand parts

63 Products

66 Readers' Exchange

68 Advertisers' Index

ON THE COVEROver the years, as electronics hasevolved, oscilloscopes have evolved.Today, they can examine more than onecircuit point at a time. Newer featuresinclude digital readout of signal levelsand frequencies and because of the con-stantly shrinking size of microelectron-ic components and ICs, oscilloscopescan be made increasingly portable.(Photo courtesy Fluke)

April 1994 Electronic Servicing & Technology 1

Editorial

A mysterycleared up

A number of readers have written orcalled looking for an address or tele-phone number for a company calledMultitech/Dynatech, a manufacturer ofVCRs and televisions. After muchsearching, and a great deal of help froma number of people, we have found outthe situation on Multitech/Dynatech.

Multitech/Dynatech is no longer inbusiness. It was a division of a con-glomerate based in Holland. I got thisinformation from the management atCRC Components, Inc.

Limited supplies of some Multitechcomponents are available from CRC atthe following address:

CRC Components, Inc.186 University ParkwayPomona, CA 91768Order desk: 800-822-1272Fax: 909-594-4761

CRC is a major distributor of flybacktransformers, integrated circuits andtransistors for consumer electronicsproducts such as televisions and com-puter monitors. They also carry servic-ing information such as schematic dia-grams for monitors. They do nothowever, do servicing.

For your further information, at onetime CRC operated a division calledTransworld Electronics that handled theMultitech parts, but that group's func-tions have been incorporated intoCRC's Parts/Order department, andthus no longer functions as a singledivision.

Computers are consumer productsOver the past few years, more and

more individuals have been purchasingpersonal computers for home use.Because of this increasing number ofcomputers in homes, an increasingnumber of service centers have begunto service computers. If there was anydoubt remaining that computers werebecoming firmly ensconced as a con-sumer product, an article in the KansasCity Star of Tuesday January 25, 1994,based on recent consumer researchshould dispel it.

According to the column, estimatesby Channel Marketing and IDC, bothwell-known high-tech market researchfirms, indicate that more than half of allcomputer sales in 1993 were for homeuse, surpassing corporate computer pur-chases for the first time.

It was clear three years ago, the arti-cle continued, that this was going to hap-pen. The falling cost and rising powerof machines and software were turningthe PC into a home entertainment, edu-cation and business machine.

Most home users of personal com-puters have incomes higher than$50,000 a year, and one quarter of themhave incomes higher than $70,000 ayear. The higher the income level, infact, the more certain it is that they havea personal computer. About one -fifth ofcomputer households have more thanone machine.

Finding computer partsNow that personal computers have

become as much a part of the consumerelectronics product mix as TVs, VCRs,CD players and microwave ovens, theowners of these products will expect tobe able to bring them into the local con-sumer electronics service center andhave them serviced. That's a wonderfulopportunity for those service centerswho are prepared to offer that service.

It's a problem as well, though, becausemany personal computer and monitormanufacturers seem to be intent onkeeping information and replacementcomponents from independent ser-vicers. Because this is a serious problem,we have provided a partial solution to itin this issue. This month's ComputerCorner, titled "Sources for MonitorSchematics and Parts," provides readerswith useful information on who providesservice literature and parts and who doesnot, and offers some alternative sourcesof parts and information.

As computer service and replacementparts information becomes available,we'll share it with you.

2 Electronic Servicing & Technology April 1994

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PROCESSK/NAL MAGAZINE FOR ELECTRONICS AND C OMPLRIP SERVICINGNewsVideo market gains

eight percent in 1993The video market gained eight percent

in 1993 over 1992 on the strength of all-time records for annual sales volume ofdirect view color televisions, projectionTVs, VCR decks, camcorders, and TV/VCR combination units, according to theElectronic Industries Association's Con-sumer Electronics Group (EIA/CEG).

"1993 should be viewed as a spectacu-lar year for the consumer electronics in-dustry," says Joseph P. Clayton, Execu-tive Vice President, Marketing & Sales-Americas & Asia, Thomson ConsumerElectronics. "As the final quarter ap-proached, the industry shifted into highgear, racing to new records for color TVand VCR unit sales and eclipsing the threemillion mark for camcorders.

"A relatively new category, TV/VCRcombos, was a runaway best-seller witha 74 percent unit sales increase over 1992.High end sales, the industry's profitabilitygauge, continued to climb with big -screencolor TV unit sales leading the way.

"The successes of 1993 reflect the con-sumer's satisfaction with the performanceof consumer products and an awarenessof their value. As the home theater trendexpands and digitally -driven productsemerge, industry results could improveeven more dramatically."

Sales of direct view color TVs rose avery strong nine percent in 1993, bestingthe eight percent gain recorded in 1992.Sales broke the 23 million unit mark forthe first time ever, surpassing the previ-ous all-time high of 21.7 million units setin 1989. Large screen TV sales (27 inch-es and over) were strongest among cate-gory performers in 1993, jumping 28 per-cent to sales of 4.5 million units. Themarket leaders in terms of sales volume,however, were 19- and 20 -inch sets,which together rose four percent in 1993,with sales totaling nearly 9.6 million.

Projection television sales ended 1993over 465,000 units strong-a 15 percentgain over 1992. This was the best annualgrowth for the category since the 29 per-cent increase of 1990. Sales of sets 49 -inches and under closed out 1993 with asix percent gain, while sets 50 inches andover tripled that gain with an 18 percentincrease, and sets 55 inches and over rosenearly 11 times that much.

VCR deck sales rallied in the latter part

of 1993 to finish the year with a secondconsecutive all-time record, realizingsales of nearly 12.5 million units. Salesof stereo models surged 10 percent.

Camcorders passed the three millionunit mark in 1993, and posted a 10 per-cent increase in sales to dealers. Full-sizecamcorders rose 16 percent during 1993,with sales totaling just over 780,000 units.Compact camcorders rose eight percent.

TV/VCR combination units closed outa phenomenal sales year, rising 74 per-cent with sales of 1.6 million units. Thesecond half of 1993 was particularlystrong for the category, as monthly growthnever dropped below 52 percent, whileaveraging 64 percent.

EIA applauds FCC on itsendorsement of the grand alliance

HDTV standard proposalThe Electronics Industries Association

(EIA) and its Advanced Television Com-mittee applaud the recent unanimous ac-tions by the Federal CommunicationsCommission (FCC) and the FCC Advis-ory Committee on Advanced TelevisionService for its endorsement of the GrandAlliance standard proposal for digitalhigh -definition television (HDTV) andits recommendation to construct hard-ware for system verification testing.

In letters to FCC Chairman Reed E.Hunt, Secretary of Commerce Ron Brownand Assistant Secretary Larry Irving(NTIA), as well as House Telecommuni-cations and Finance SubcommitteeChairman Ed Markey, EIA stated that it"recognizes the broad benefits that theimplementation of a digital HDTV sys-tem will bring to U.S. consumers, pro-viders and electronics manufacturers.

"The implementation of the Grand Al-liance HDTV system will also serve as animportant element of the National Infor-mation Infrastructure (NII), particularlyin relation to bringing the benefits of theNII to consumers."

The Association explained that thetechnical characteristics of the Grand Al-liance system are responsive to the needsand concerns of consumers, broadcasters,cable operators in the computer industry,along with the telecommunications in-dustry and manufacturers.

114P111101118ServicingTechnology

Electronic Servicing & Technology is edited for ser-vicing professionals who service consumer electronics

equipment. This includes service technicians, field ser-

vice personnel and avid servicing enthusiasts who repair

and maintain audio, video, computer and other con-sumer electronics equipment.

EDITORIALNils Conrad Persson, EditorLinda Romanello, Assistant Editor

CONSULTING EDITORSHomer L.Davidson, TV Servicing ConsultantVictor Meeldijk, Components ConsultantJohn E. Shepler, Audio ConsultantSam Wilson, Electronics Theory Consultant

PRODUCTIONElizabeth Ryan, Art DirectorBarbara Terzo, Assistant Art DirectorSusan Reale, ArtistEdmond Pesonen, Electronic Composition Mgr.Dorothy Kehrwieder, Production ManagerEmily Kreutz, Adverising ProductionPat Le Blanc, Phototypographer

BUSINESSRichard A. Ross, PublisherJohn Dorr, General ManagerFrank V. Fuzia, ControllerCatherine Ross, Circulation DirectorMelissa Kehrwieder, Data Processing ManagerCarol Licata, Data ProcessingDenise Pyne, Customer Service

SALES OFFICEElectronic Servicing & Technology76 N. Broadway, Hicksville, NY 11801516-681-2922; FAX 516-681-2926

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Electronic Servicing & Technology (ISSN 0278-9922) ispublished 13 times a year by CO Communications, Inc. 76N. Broadway, Hicksville, NY 11801. Telephone (516) 681-2922. Second class postage paid at Hicksville, NY andadditional offices. Subscription prices (payable in US dol-lars only): Domestic-one year $24.75, two years $45.Foreign countries-one year $30.75, two years $57. Entirecontents copyright 1994 by CO Communications, Inc.Electronic Servicing & Technology or CO Communi-cations, Inc. assumes no responsibility for unsolicitedmanuscripts. Allow six weeks for delivery of first issueand for change of address. Printed in the United Statesof America.

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The interoperability characteristics ofthe Grand Alliance system also will con-tribute to the expansion of the NII. Final-ly, and of equal importance, the develop-ment of the Grand Alliance system, andthe expeditious approval of an Americanhigh definition standard, will promoteU.S. competitiveness and create thou-sands of skilled, high -paying jobs in theUnited States.

The letters, signed by EIA PresidentPeter F. McCloskey and ATV CommitteeChairman Sidney Topol, concluded bysaying, "The FCC/ACTS endorsement ofthe Grand Alliance system is an essentialprerequisite to the rapid development anddeployment of an interoperable high -def-inition television system in the UnitedStates. EIA and its Advanced TelevisionCommittee encourage the FCC to com-plete testing and deliberations and adoptan American standard for high -definitiontelevision at the earliest possible date.EIA hopes that swift action by the FCCwill allow a demonstration transmissionof the 1996 Summer Olympics in highdefinition which will accelerate the ac-ceptance of the exciting new entertain-

ment, information and multi -media ser-vices that digital HDTV promises to de-liver to American homes."

The Digital HDTV Grand Alliance rep-resents the merging of technologies de-veloped by three groups that had beenvying for the digital HDTV standard inthe United States: AT&T and ZenithElectronics Corporation, General Instru-ment Corporation and the MassachusettsInstitute of Technology, and a consortiumcomposed of Thomson Consumer Elec-tronics, Philips Consumer Electronicsand the David Sarnoff Research Center.

Industry groups create alliance tosponsor management education

The National Association of ServiceDealers (NASD), a division of the Na-tional Association of Retail Dealers ofAmerica (NARDA), and the NationalElectronics Service Dealers Association(NESDA) have joined forces to co-spon-sor the 1994 NASD/NESDA School ofService Management. This was an-nounced jointly by the president ofNASD, Roberta Chesney, Quality TV,Florida, NY and NESDA president, Rob-

ert Masa, Electra Sound, Parma, OH. Theschool will be held October 8-11, 1994at Stouffer's Atlanta Concourse, At-lanta, GA.

"This is a perfect example of the valueof alliances for creating new benefits,"according to NASD president, Chesney."NASD has built a reputation for excel-lence in management education. NESDAis known throughout the industry for itsequally excellent technical training. Ourstaffs will be working together to createa management program that serves theneeds of both memberships."

The annual School of Service Manage-ment was started in 1958 by what wasthen the service division of NARDA. It isan intensive four -day management pro-gram for service business owners andmanagers and the service managers ofself -servicing retailers.

Servicers who attend can study everyaspect of managing a professional servicecompany or department. The programwill include classes on finance, parts in-ventory and personnel management, mar

(Continued on page 64)

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Oscilloscope update-An oscilloscope refresherBy The ES&T Staff

When the first oscilloscope was con-ceived and built, the world of electronicschanged forever. It became possible to ac-tually see what was going on in an elec-trical or electronic system, to observe thewaveforms and to determine if the circuitwas working as it should.

The oscilloscope helped circuit design-ers visualize the results that they wantedfrom their circuits, helped testers deter-mine if the finished products were per-forming as specified, and aided servicingtechnicians in diagnosing problems in cir-cuits that were not performing accordingto the design.

The evolutionEarly oscilloscopes were crude when

judged by today's standards. They pro-vided only synchronous sweep. So, if awaveform was irregular it was difficult,if not impossible, to observe it. The band-width of the first scopes was narrow, soonly a small range of signals could be ob-served. These scopes were single channel,so the waveform at only one test pointcould be observed at one time. It was notpossible to compare waveforms.

Over the years, as electronics in gener-

al has evolved, oscilloscopes have evolvedtoo. Today, oscilloscopes can be used toexamine more than one circuit point at atime. Bandwidths well over 300MHz arepossible. Oscilloscopes now have a trig-gered sweep function that uses a part ofthe observed waveform to trigger the sweeposcillator so that almost any waveform, nomatter how irregular, can be displayed.

Oscilloscope trends todayEven though the oscilloscope has by

now attained the status of being a vener-able old instrument, constant improve-ments are being made to the instrumentitself and to accessories associated withthe oscilloscope.

For example, in the relatively recentpast, oscilloscope manufacturers haveadded such features as digital readout ofsignal levels and frequencies. Digitalstorage oscilloscopes allow users to storea waveform for later analysis, or compari-son with other waveforms. The ability tostore a waveform also implies the abilityto put a copy on disk and analyze it any-where, at a later time.

Other changes in the world of oscillo-scopes include such innovations as turn-

ing a personal computer into a digital stor-age oscilloscope, and the development ofprobes that can turn an oscilloscope intoa spectrum analyzer or a logic scope.

An oscilloscope refresherBecause the oscilloscope is most like-

ly the single most important, useful, pieceof test equipment available to the servicetechnician, we're presenting this specialupdate that provides a refresher on oscil-loscope operation (based on informationfrom the Panasonic electronic measuringinstrument catalog), provides specificsuggestions for using an oscilloscope todiagnose and service the microprocessorsthat are cropping up in every type of con-sumer electronics product, and reports onsome recent advances in oscilloscopes.

The oscilloscope displayIf a varying electrical signal is repeti-

tive, there are two ways of making the sig-nal stand still on the CRT screen. In thesynchronous sweep method, the sawtoothsignal applied to the horizontal deflectionplates is chosen so that the repetition rateof the signal applied to the vertical deflec-tion plates is an integral multiple of it.

INPUT TERMINAL

0 ATTENUATOR -311 VERTICAL -AXISAMPLIFIER

SAWTOOTH WAVE GENERATOR CIRCUIT

TRIGGER SIGNALGENERATOR CIRCUIT

HORIZONTAL -OUTPUT

AMPLIFIER

BRIGHT -LINE ERASE SIGNAL

DO

CRT CIRCUIT

H

CRT

Figure 1. Most modern oscilloscopes use the trigger sweep method of developing a display.


This makes the displayed waveform standstill. Depending on the multiple chosen,one, two, or more complete cycles of thewaveform may be displayed.

This method is not suitable for high fre-quency signals or extremely low frequen-cy signals. Some waveforms cannot bemade to stand still by this method. Forthese reasons, synchronous sweep is notcommonly used today.

In the trigger sweep method, a pulsewaveform is generated from the signal tobe measured, or from a part of a signalrelated in time to the signal to be mea-sured to start the sawtooth signal. Thisderived signal is called the "trigger." Thetrigger method makes it possible to ob-serve even complicated waveforms at thesame position regardless of frequency.The trigger sweep method is very effec-tive for measuring pulse waveforms.Most modern oscilloscopes employ thismethod (Figure 1).

Selecting an oscilloscope basedon specifications

The type of oscilloscope needed by atechnician depends on what work is goingto be performed using the oscilloscope,and the demands of that work. For exam-ple, the demands of a TV/video servicecompany will be considerably less thanthose of a digital circuit design company.On the other hand, the demands of anoscilloscope used by a TV/video serviceorganization will be considerably greaterthan one used by a company that doesstrictly electrical or audio work. The dig-ital circuits of today's audio productshave, however, certainly imposed greaterdemands on the test equipment than thestrictly analog audio of a few years ago.

Frequency bandwidthIdeally, the frequency response of an

oscilloscope is designed as shown in Fig-ure 2 so as to faithfully amplify a pulsewaveform. Faithful rendition of a pulseimplies that the oscilloscope amplifierwould amplify all frequencies equally. Inthis figure, f0 is the point where the ampli-tude is 3dB below the reference ampli-tude. At this frequency, the amplitude is0.707 of the amplitude at the referencefrequency. This point is the upper limit offrequency bandwidth. If a sine wave witha frequency of 100MHz is displayed onan oscilloscope that has 100MHz band-width, the amplitude of the sine wave dis-

REFERENCEAMPLITUDE

1.]

0.5

0.1

0.5

tl

0.997 J 917

110 0.1 0.05 1 2 3 10

NORMALIZED FREQUENCY MO (LOG)

Figure 2. Ideally, the frequency response of an oscilloscope is designed so as to faithfully ampli-fy a pulse waveform.

(A)

(B)

0.1A

PULSE

AMPLITUDE A 0.8A

0.1

1I

1.1 NRISE TIME PULSE WIDTH FALL TIME

(HALF AMPLITUDE DURATION)

0.5A

0.5A

- TOP LINE

BASE LINE

Figure 3. The oscilloscope is frequently used for measurement of pulse waveforms. An idealpulse waveform is shown in Figure 3a. Such a pulse shape cannot actually be achieved, how-ever. An actual pulse waveform is shown in Figure 3b.


II

TR

-11111.1 kil-1 I

To

ACTUAL WAVEFORM

DISPLAYED WAVEFORM

TR = siT02 - 3.52

TP = MEASURING TIMEFOR OSCILLOSCOPE

: TR = RISE TIME OFINPUT SIGNAL IN nS

Figure 4. When you measure a pulse waveform, you have to consider the bandwidth of the oscilloscope, depending on the rise time of the pulse.The measurement error includes the rise time for the measuring oscilloscope. This figure shows the measurement on a pulse waveform using a100MHz oscilloscope.

played will he about 30% lower than theactual amplitude.

As shown in Figure 2, the response is8% below reference amplitude at a fre-quency equal to 1/2 the frequency band-width and 0.3'4 from the reference ampli-

tude at a frequency equal to 1/10 of thefrequency bandwidth.

When you're using an oscilloscope toobserve sine waves, keep this amplitudereduction effect in mind, or you might getsome confusing results.

Rise timeThe oscilloscope is frequently used for

measurement of pulse waveforms. Anideal pulse waveform is shown in Figure3a. Such a pulse shape cannot actually beachieved, however. An actual pulse

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INPUT TERMINAL

ATTENUATORVERTICA _-AXIS

AMPLIFIER0-10

SAWTOOTH GENERATOR CIRCUIT

TRIGGER SIGNALGENERATOR CIRCUIT

[ SIGNAL DELAYCIRCUIT

HORIZONTAL -AXISAMPLIFIER

BRIGHT LINE ERASE SIGNAL

VERTICAL-OUTPUT

AMPLIFIER

CR7 CIRCUIT

CRT

Figure 5. The sweep magnifier makes it possible to magnify the observed waveform to the left and right, with the CRT center as the centerofthe waveform. Here the waveform is magnified 10 times by switching the horizontal amplifier gain.

waveform is shown in Figure 3b. This fig-ure defines each part of the waveform.

The speed at which the waveform risesis expressed by the "rise time." In Figure3, the time during which the amplitudechanges by 0.8A is called the rise time.

Rise time and bandwidthBandwidth is one measure of the capa-

bility of an oscilloscope. A pulse wave-form can be shown to consist of an infi-nite number of sinewave components.Each of these components has its ownamplitude and phase. If the bandwidthand risetime of the amplifier in the oscil-loscope used to display these componentsare maintained in this relationship: Tr xB = 0.35 (where B is the 3dB bandwidth

and Tr is the risetime), then it will be pos-sible to amplify, and thus display, thewaveform without any distortion.

This expression indicates the rise timethat appears at the output of the amplifi-er system when an ideal pulse waveformwith a rise time of 0 is applied to an ampli-fier system with bandwidth B. The rela-tionship described by this expression

From the technicians and editorsof PHOTOFACT®!To fulfill the industry's demand forVCR service data, Howard W.

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Sams' complete, consistent standard -notationschematic designs by circuit board withcabling notations for less than the cost ofmanufacturers' data.

Electronic parts list. Waveforms, voltages, and IC functions. Grid locator and call outs. Interconnect wiring diagram showing

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EXTTRIG

0INT

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Figure 6. Delayed sweep can be operated in either of two modes. In one mode, B sweep startsimmediately after delay time, td, has elapsed (waveform shown in Figure 6a. In the other mode,B sweep is started with a B trigger pulse after td has elapsed (waveform shown in Figure 6b).

makes it possible to determine the ampli-fier characteristic for an oscilloscope. Forexample, from the equation, the rise timewith a 100MHz bandwidth is Tr = 0.35/B= 0.35/100 x 106 = 3.5ns

When you measure a pulse waveform,you have to consider the bandwidth of theoscilloscope, depending on the rise timeof the pulse. The measurement error in-cludes the rise time for the measuring os-

cilloscope. Figure 4 shows the measure-ment on a pulse waveform using a 100MHz oscilloscope.

Input impedanceThe rise time of an oscilloscope is relat-

ed to the input impedance by this expres-sion: Tr = 2.2(Re)(Cin). In this equation,Re is a value determined by Rs in the mea-sured circuit and input resistance, Rin ofthe oscilloscope, and Cin is the input ca-pacitance of the oscilloscope. The risetime can be measured as shown in the fol-lowing expression by connecting the 10:1probe to the signal source, provided thatthe input impedance of the oscilloscopeis 10M0/20pF and Rs is 3000:

Tr = 2.2 x 30011 x 15pF = 9.9ns

SensitivityThe vertical -axis sensitivity of an oscil-

loscope is expressed as volts per division(V/div). The peak -to -peak amplitude ofthe waveform being observed is adjustedby the sensitivity switch to make it easyto observe. For example, a 2Vp-p signalis being observed with the oscilloscope.

If you have the oscilloscope set to I V/division, the signal will be spread verti-cally over two divisions. If you set the os-cilloscope to the 0.5V/division range, thesignal will occupy four vertical divisions.The voltage of any input signal can bemeasured by multiplying the number ofvertical divisions covered by the dis-played signal times the V/div setting.


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Sweep rateThe horizontal sweep rate of an oscil-

loscope is measured in seconds/division.This magnitude is calibrated by the timeper division on the CRT screen.

The amount of time required to movethe spot horizontally the distance of onedivision is called the sweep rate. Sweeprate is expressed in seconds per division.

Signal delay timeIn the trigger sweep method, the oscil-

loscope generates a trigger pulse to drivethe sawtooth generator circuit from thesignal output of the vertical -axis amplifier.

If the signal being observed has a fastrise time, the amount of time the signaltakes to reach the vertical deflectionplates is less than the amount of time ittakes for the trigger signal to trigger a

sweep on the horizontal axis. When thishappens, the rising edge of the signal can-not be observed.

To correct this problem, a signal delaycircuit is added to the vertical -axis ampli-fier circuit to delay the signal before it isapplied to the vertical deflection plate.

Sweep magnifierThe sweep magnifier makes it possible

to magnify the observed waveform to theleft and right, with the CRT center as thecenter of the waveform. Figure 5 showsan example of magnifying the waveform10 times by switching the horizontal am-plifier gain.

If a waveform is magnified 10 times,the sweep time per division on the CRTscreen is 1/10 the sweep time per divisionto display the waveform normally. If a

waveform is displayed normally at a giv-

en sweep rate, when it is magnified 10times the sweep rate becomes one tenththe normal sweep rate.

Delayed sweep

When you're observing a complicatedwaveform on the oscilloscope you may

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11

Oscilloscope Update:Turning a scope into something else and turning acomputer into a scope

An oscilloscope is essentially a devicefor turning a signal that's applied at itsinputs into a display that the user can in-terpret, and, on the basis of that inter-pretation, decide if the circuitry that'sproducing that signal is operating cor-rectly.

In most cases, the signal to be viewedis a voltage that's varying in some way.And the intention is to look at the timevariation of that signal.

But sometimes the oscilloscope userwould really like to observe the fre-quency spectrum associated with thesignal being observed. And sometimesthe oscilloscope user would really like toobserve the relationship of the logic sig-nals at a number of points in the circuit;as on a data bus.

To observe these kinds of signalswould ordinarily require a spectrum ana-lyzer or a logic scope. Given theadvanced state of electronics today, andthe extremely small size of ICs and com-ponents, engineers have found ways tocram enough circuitry into a relativelysmall probe that will give an oscilloscopethe ability to perform, to some degree,the functions of a logic scope or spec-trum analyzer.

A logic probeITT Pomona has recently introduced a

device called a Logic Scope Probe,which is connected to the input of anoscilloscope. The logic scope probe isthen connected to the points of interestin the digital circuit to be observed. Theprobe converts the several inputs intoan output signal to the oscilloscopewhich displays up to eight logic signalsat the same time, in their correct timerelationship.

This unit can be used in one of threedifferent modes.

In the logic analyzer mode, the oscil-loscope becomes an 8 -channel logic ana-lyzer with a memory depth of 16 words.Each channel is displayed as one hori-zontal line on the oscilloscope's screenin a "timing diagram" fashion.

In the trigger probe mode, the probegenerates a real-time trigger signalwhenever an 8 -bit user -selected condi-tion is met. You can use this mode to viewanalog signals (using your passiveprobes) while you trigger your oscillo-scope externally from a digital combina-tion.

In the MUX mode, the user can watch,in real time, 8 digital signals simultane-ously on screen. The oscilloscope is trig-gered as in the trigger probe mode.

A spectrum analyzer probeA spectrum analyzer provides a dif-

ferent way to look at a time varying sig-nal. An oscilloscope gives a display ofthe signal in the "time domain." a spec-trum analyzer provides a display of thesignal in the "frequency domain."

As an example, as we said earlier inthis article, a square wave can be con-sidered as being composed of an infinitenumber of sinewaves. The oscilloscopedisplay shows the composite of all ofthose sinewaves in the time domain: asquarewave.

The spectrum analyzer, in contrast,displays the frequency components ofthe square wave in the frequencydomain. This display is made up of anumber of vertical spikes rising from thehorizontal signal baseline at the funda-mental frequency and each harmonic.Each of these spikes shows the amplitude

of the sinewave component at each har-monic.

While the oscilloscope time domaindisplay of a signal is the most useful fora service technician, there are timeswhen a frequency domain display wouldbe useful. In many service centers, how-ever, a spectrum analyzer cannot be costjustified.

An alternative to a dedicated spectrumanalyzer is the spectrum analyzer probe.Of course, the amount and quality ofspectrum information the probe can pro-vide is limited, compared to the infor-mation provided by a spectrum analyzerprobe. However, many times even limit-ed information is better than no infor-mation at all.

The personal computer asan oscilloscope

While some engineers have been de-signing probes that extend the usefulnessof the oscilloscope, still other engineershave been designing circuitry that con-verts the increasingly popular computerinto an oscilloscope.

The oscilloscope front end for the per-sonal computer contains the circuitrythat senses the signal from the unit undertest and converts the signal from analogto the digital equivalent. Also part of thepackage is software that formats the dis-play screen so that it looks like an oscil-loscope, and displays the signal on thescreen.

Of course, because this is a computer,it is possible to do the same kinds ofthings with the oscilloscope data as canbe done with any other computer data:store it, manipulate it, compare it withother data, put it on a floppy disk andexamine it later, and more.

want to magnify a portion of it so you canlook at it more closely. You can do this ifyour oscilloscope has the feature calleddelayed sweep. Ordinarily, the mainsweep is called the A sweep and the de-layed sweep is called the B sweep. The

sweep waveform of A sweep is sent to thedelayed trigger signal. This delayed trig-ger signal starts B sweep. Figure 6 is ablock diagram of this circuit.

Delayed sweep can be operated in ei-ther of two modes. In one mode, B sweep

starts immediately after delay time, td,has elapsed (waveform shown in Figure6a). In the other mode, B sweep is start-ed with a B trigger pulse after td haselapsed (waveform shown in Figure 6b).

With delayed sweep you can accurate -


SELF OSCILLATING INTHE CHOPPING MODE

CHANNEL 1PREAMPLIFIER

CHANNEL 2PREAMPLIFIER

DISPLAY FUNCTIONCONTROL

CH1. CH2, CHOPALT. X -Y. ETC.

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Figure 8. Two channel switching on an oscilloscope is accomplished as shown here

ly determine the delay time by means ofthe turn pot. Any part of the waveformcan be magnified and observed.

Dual trace and dual beamMany times it's desirable to observe

two waveforms at the same time. For ex-ample, a technician might want to look atthe input signal into an amplifier, and ob-serve the amplified signal at the output atthe same time. A two channel oscillo-scope allows for this. Two electron beamscan be generated to display two lines onthe CRT screen. Alternate display andchopping can also be employed for real-time switching of one electron beam.

Alternate display and choppingDual trace realtime display of two sig-

nals can be done in one of two ways: alter-nate display and chopping. In the alter-nate display mode, the first sweepdisplays the channel- I signal and the sec-ond sweep displays the channel -2 signal,as shown in Figure 7. Dual trace opera-tion is thus possible if the two signals havethe same periodicity.

In the chopping mode, the channel -1and channel -2 signals are chopped intopieces and are displayed alternately dur-

ing the same sweep, as shown in Figure7. In chop mode, either random or repet-itive signals can be observed.

When the sweep rate is high, however,the chopped segments are too noticeableon the screen. Ordinarily, the alternatemode is used at high sweep rates, and thechopping mode is used for slower rates.

Two channel switching circuitTo achieve a two -channel display, the

signals output from the channels I and 2preamplifiers are applied to the switchingcircuit, which is driven by the signal from

the channel switching signal generatorcircuit. In the alternate display mode, thegate pulse from the time -axis circuitswitches the channel during the blankingperiod. In the chopping mode, the oscil-lator built into the switching signal gen-erator circuit switches the channel in theoscillation cycle. The part of the signalwhich would be displayed during switch-ing is blanked because this would makeit hard to observe the waveform. This iscalled chop blanking. Figure 8 shows ablock diagram of a two -channel switch-ing circuit.

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Testing microprocessors using anoscilloscopeBy The ES&T StaffBased on Sencore Tech Tip 109

Microprocessors are now being used tocontrol every kind of consumer electron-ics products: TVs, VCRs, CD players,and microwave ovens. Many techniciansthink that these microprocessors are dif-ficult to service. It may be that these tech-nicians think of microprocessors as com-puters. Most microprocessor systems areused as controllers, however, not as com-puters. Knowing this, and knowing howto approach microprocessors with famil-iar test equipment can make servicingmicroprocessors a lot less fearsome.

Microprocessors rarely failLet's start with a piece of practical ad-

vice: don't be too quick to change the mi-croprocessor. Time and time again, tech-nicians find that changing a microproces-sor doesn't help a problem that looks likeit might be caused by a bad micro. Micro-processors rarely fail. They are protectedfrom static discharge and power linesurges by filtered power supplies and bybuffering transistors and ICs. The bestprocedure to follow when you suspect afailed microprocessor is to leave it onyour list of suspects, but be sure to inter-rogate all the other likely culprits first.

You can quickly isolate most micro-processor -related problems using an os-cilloscope and five quick tests to be de-scribed a little later. First, let's see how amicroprocessor used as a controller dif-fers from one used as a computer so thatyou can see why the approach to micro-processor servicing is different from theapproach to computer servicing.

The computer vs the controllerThe biggest difference between a mi-

croprocessor used in a computer and oneused as a controller has to do with pro-gramming. A computer can be repro-grammed as needed, usually by enteringinformation from a magnetic disc or tape.The controller, on the other hand, lives arelatively boring life, playing the sameprogram over and over. Microcontrollers

Figure 1. The main difference between a computer and a controller is that the computer may beeasily reprogrammed from a disk or a tape. It also has external memory and complex inputs andoutputs.

are rarely reprogrammed once the systemhas left the factory. This main differenceleads to several other differences as well.

Computers, whether desk -top person-als or large mainframes, handle large vol-umes of assorted data. One batch may benumbers for a payroll, and the next maybe a document for a word processor. Con-trollers, by comparison, deal with muchsmaller volumes of data. The data are re-petitive and predictable, often represent-ing inputs from simple switches and sen-sors within the system.

The microprocessor used in a comput-er connects to thousands or millions ofbytes of external random-access memory(RAM), each byte containing 8 memorylocations. This RAM may require dozensof external memory chips. The micro-processor used as a microcontroller onlyneeds a small amount of memory, ofteninside the microprocessor chip itself.

Lastly, a computer has complex inputsand outputs. Inputs come from key-boards, disk drives, or modems. Outputsfeed printers, plotters, CRT displays, orother computers. The controller only hasinputs from a few switches or sensors. Itonly feeds a few ICs, relays, and a sim-ple digital display.

Servicing controller -type microproces-sors doesn't need to be any more compli-cated than servicing any integrated cir-cuit. The limited environment of thecontroller means that you don't have toknow many things that you might thinkyou need to know.

The simplified systemOne of the biggest differences between

servicing computers and controllers isthat you don't have to worry about soft-ware problems in controllers. You don'tneed to know programming or ASCII


Keyboard

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Figure 2. The microprocessor used as a controller is programmed one time at the factory. It usessimple switches and sensors for inputs, and transistors, ICs, relays and digital displays for outputs.

codes. If you suspect a software problem,you have only one option: change the pro-gram chip.

Second, you don't have to sort throughrows and rows of memory chips. Thismeans that you don't need a $20,000 logicanalyzer or an 8 -channel scope to vieweach byte of data separately in order tolocate a defective memory location. If aninternal memory location is bad, you haveto change the microprocessor.

Finally, the controller has limited in-puts and outputs: generally no more thaneight of each. You can test each one sep-arately to confirm whether the problem iscoming from inside the microprocessororfrom an external component.

Once you stop worrying about soft-

ware, memory, and complicated interfacesystems, the microprocessor takes on awhole new look. You can find most prob-lems with five standard tests using anoscilloscope. The tests are of:

The power supply The clock The input and output lines The reset circuit The grounds

Test the power supplyAlways test the power supply first,

whether the problem is a totally deadmicro or one with erratic operation. Startwith the dc level. Set the oscilloscope for

Figure 3. Most defects in a microcontroller system are caused by problems outside the microprocessor. Test the microprocessor inputs andoutputs in this sequence to isolate externalproblems before replacing the microprocessor.

dc input, and set the trace at the zero level.Touch the probe to the power supply pinand observe the dc level on the scope, orcheck the scope's digital readout to deter-mine the dc voltage. The voltage shouldordinarily be in the range of 5 to 12 volts.The voltage you observe should be with -

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Figure 4. Watch for a reset pulse when you first apply power. Defective reset circuits make the microprocessor appear defective because it doesnot start at the beginning of the program.

in about 0.2V of the specified level.But don't stop there, because noise of-

ten enters the microprocessor through thepower supply, causing it to act erratical-ly. Check the CRT to confirm that the sig-nal is clean. If the oscilloscope has a dig-ital readout, use the appropriate proce-dure to obtain a digital readout of the peak -to -peak voltage. This will give you anindication of the magnitude of the ripple.

You may see 60Hz ripple from a badfilter or regulator. Or you may see highfrequency digital noise from anotherstage, which can cause the micro to freezeas the noise pulses intermix with normalinput signals. If so, suspect a bad filter ordecoupling capacitor on the power sup-ply line, or a bad IC on the same line thatis loading the supply. If the microproces-sor has more than one power supplysource, check the other sources in thesame manner.

Test the clock

A problem in the crystal -controlledclock can cause intermittent operation.Watch for the following conditions as youprobe one, then the other of the micro-processor pins, connected to the clock in-put pins, usually coming from a crystal.

First, adjust the scope to achieve a sta-ble trace and note the period of the wave-form. The frequency is the inverse of theperiod. If your oscilloscope has a digitalreadout, use the appropriate procedure todisplay the frequency. If the frequency isnot in agreement with the specification,suspect that the crystal is bad.

Next note the amplitude of the crystaloutput to make sure that it is in accordancewith the specification. Even if the crystalfrequency is correct, if the amplitude isbelow the threshold needed by the micro-processor, the clock information might

not be reaching the clock.Finally, look carefully at the clock

waveform to be certain that the clock doesnot include extra "glitch" signals. Theseextra signals might cause the micro-processor to intermittently skip a programstep, or could cause the whole system torun too fast. The clock should be a cleansine or square wave.

Test the input linesGenerally, input defects affect only a

few functions. Use the product's controlbuttons, knobs and other controls to tryevery function controlled by the microand note which ones work correctly andwhich ones have troubles. Then, deter-mine which input pins are associated withthe bad functions. For example. one ortwo switches might provide an input to asingle function and not be used with anyother of the micro's inputs.


Connect the scope probe to the pinsassociated with the questionable func-tions and observe the trace as you cyclethe input switches. Either on the trace oron the digital readout, note the dc levelwith the switch contact open and with itclosed to be sure that the level properlychanges between the one and the zerologic level. Be sure that neither level fallsinto the "undefined" area between the twologic levels, or the microprocessor mightnot be able to decide whether a high or alow condition exists.

Check contact resistance or pull-up re-sistors if the levels are wrong. Watch fornoise or glitches which may cause themicro to interpret a single switch opera-tion as two or more separate switch clo-sures. Check the switch contacts, decou-pling capacitors, and switch buffer cir-cuits to isolate noise conditions.

Test the output linesNext, test all data (output) lines to be

sure that one isn't stuck at logic high orlogic low. Touch the probe to each micro-processor output pin, one at a time. Don'tworry that the signal shows a blur oflines-seemingly out of sync. This is sim-ply because of the asynchronous (ran-dom) data coming from the micro.

Set the oscilloscope to dc coupling toconfirm that the low points on the wave-form are below the minimum level for azero, and that the high points are abovethe minimum level for a one. Suspect abad pullup resistor or an IC outside themicro if the signals are falling betweenlogic levels.

If the signal at a pin remains cementedto ground or B+, look at the schematic tosee when that pin is used. You might haveto trace the pin to a relay or an IC to findout which functions it controls. Thenforce the microprocessor into a functionthat uses this pin by pressing a button orcycling a sensor.

If the signal at the pin doesn't change,isolate the pin from the external circuitsby carefully removing the solder betweenit and the foils on the pc board. Connectthe oscilloscope to the isolated pin andagain check for toggling. If the pin tog-gles with the load removed, the problemis most likely outside the micro: an exter-nal component is holding the pin high orlow. Isolate each component on that line,one at a time, until the line toggles. Thenreplace the defective part.

If the pin remains stuck after being iso-lated, it's beginning to look more like adefective microprocessor, but don't un-solder the other legs yet. There are twomore checks to make.

Test the reset circuitMicroprocessors need an external reset

pulse at turn -on. Without the reset pulse,the microprocessor starts in the middle ofthe program, resulting in totally unpre-dictable operation.

Take advantage of the oscilloscope'sCRT to check the reset pulse. Set the Trig-ger Source switch to channel A, the Trig-ger Mode switch to "Norm" and the Trig-ger Level control to the zero at the centerof its rotation.

Connect the device containing the mi-croprocessor to a switched ac outlet strip,so you can turn the power off and on.Don't rely on the device's power switch,since the microprocessor often receivespower independent of the power switch.In fact, many "power" switches are sim-ply one of the microprocessor inputs anddon't actually interrupt the power.

Turn off the power and connect the os-

cilloscope channel A probe to the resetpin. Watch the CRT as you apply powerto the system. If you see the trace flashacross the CRT, you know a reset pulseoccurred and triggered the oscilloscope'ssync circuits. If you didn't see a trace, there

may be a problem in the reset circuits.

Check groundsIf all of the tests so far have not point-

ed to a faulty component or componentsin the circuitry surrounding the micro-processor, now the microprocessor ishighly suspect. But don't unsolder it yet.First, check every grounded pin. Eachshould show zero volts dc and 0 volts ac.If any grounded pin has a signal on it, itwill cause the microprocessor to act asthough the micro itself is bad. The pres-ence of a signal tells you that there is anopen in the grounded path: either a bro-ken pc foil or a bad solder connection. Re-pairing the bad ground will probably clearup the trouble.

If the grounds are good, replace themicro. You've already confirmed that allthe inputs and outputs are normal.

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Solving VCR system controlproblems

rthur Flas ell

A cassette is placed into the VCR andnothing happens. Or perhaps the tapeloads, plays for two seconds and stops.What is going on?

Chances are you are experiencing a sys-tem control or "SYSCON" problem. Asthe name implies, SYSCON directs everyaspect of VCR operation. It is a fairlycomplex system and numerous signals toand from the system -control micropro-cessor are necessary to make everythingtick. One improper or missing signal willshow up as a fault in some phase of theVCR's operation.

The key to troubleshooting SYSCONproblems is understanding the circuit's

Flavell is owner of an independent consumer electronicsservice center in Alaska.

operation. Armed with this knowledge, aservice manual and some basic test equip-ment, you are ready.

Test equipmentMost voltages on the system control

microprocessor are logic signals. A logicprobe is useful for initial troubleshooting.A digital VOM or high -impedance mul-timeter, oscilloscope and frequencycounter may also be needed.

SYSCON circuitsLet's examine a typical SYSCON mi-

croprocessor, its inputs and outputs andthe sources and destinations of the vari-ous signals. To simplify the explanation,only the primary control signals areshown (Figure 1).

1 - - 40OSC 1 VDD

2 - OSC 2 SERVICE 393 - RESET SP 384 - POS SW A LP 375 - POS SW B SLP - 36

6 - POS SW C PWR ON 357- POS SW D V / T 348 - CASS IN AUDIO MUTE - 33

9 - CASS UP / DN PWR LED - 3210 - DEW CYL CON 3111 - SAFETY TAB LM FWD 3012 - T PHOTO TR LM REV - 2913 - S PHOTO TR REC - 28

14 - SENSOR STILL 2715 - T REEL PULSE CM FWD 2616 - RET 0 CM REV - 2517 - RET 1 STROBE 0 - 2418 - RET 2 STROBE 1 2319 - RET 3 STROBE 2 - 22

20 - GND STROBE 3 21

SYSTEM CONTROL MICROPROCESSOR

Figure1. A typical SYSCON microprocessor, its inputs and outputs and the sources and des-tinations of the various signals. To simplify the explanation, only the primary control signals areshown here.

Pins 1 and 2, labeled OSC 1 and 2, aretied to the on -board clock oscillator. Acrystal is mounted externally on the cir-cuit board. A check with the oscilloscopeand frequency counter will determinewhether the oscillator is operating and ifit's on frequency.

Mode switch signals

Pins 4 through 7, POS A through D, areconnected to the mode switch. This multi -position switch senses the position of themechanical assembly. Depending on themode (STOP, PLAY, Fast Forward, etc.),one or more of the switch terminals willbe grounded and place a logic low onthe associated microprocessor input(s)(Figure 2.)

CASS IN on pin 8 tells the micropro-

STOP L H H

FF/REW H H L

PAUSE L L H

REVIEW H L H

PLAY H H L

Figure 2. Pins 4 through 7, POS A through D,of the SYSCON microprocessor are connect-ed to the mode switch. This multi -positionswitch senses the position of the mechanicalassembly. Depending on the mode (STOP,PLAY, FF, etc.), one or more of the switch ter-minals will be grounded and place a logic lowon the associated microprocessor input(s).


cessor that a cassette is present and initi-ates the loading process. The source of theCASS IN signal is usually a leaf -contactswitch mounted on the top cover of thecassette compartment, or on the cassettemechanism gear train.

The signal at pin 9, CASS UP/DN, tellsthe microprocessor whether the cassetteis in the up or down position. The solidline above the DN means that a logic lowis present in that condition, and is referredto as "down not." Thus, if the cassette isin the "UP" position, a logic high is ap-plied to pin 9, while a cassette in the"DOWN" position generates a logic low.Position detection comes from a leaf con-tact switch on the cassette loading mech-anism gear train.

SYSCON safety inputsThe DEW signal on pin 10 is one of a

number of safety inputs. An accumula-tion of condensed moisture in the tapepath can cause binding and damage to thevideo tape. The dew sensor changes resis-tance in the presence of moisture andsends a logic low which prevents tape mo-tion. The dew sensor is located on the rearside of the lower drum assembly. SomeVCR models have a dew warning light onthe front panel.

The SAFETY TAB input on pin 11 pre-vents recording on cassettes that havebeen record protected. The record safetysignal is provided by a switch located atthe front of the cassette compartment. Aspring -loaded activation lever on theswitch enters the cavity left by removingthe record safety tab on the cassette.

Pins 12 and 13, the takeup and supplyphototransistors are both safety and oper-ational inputs. The phototransistors de-tect visible light or infrared energy pro-duced by a sensor lamp or LED.

The takeup transistor, located on theright side of the cassette compartment,detects light when the clear leader at theend of a tape passes between it and thesensor. The signal produced initiatesauto -rewind.

The supply transistor, located on theleft side of the cassette compartment, gen-erates a signal when it detects lightthrough the clear leader as the beginningof a tape passes between it and the sensorlight. This signal causes the VCR to ceasethe rewind function.

If both transistors sense light at thesame time (as when no cassette is pre-

RET 0

RET 1

RET 2

STROBE 0 STROBE 1 STROBE 2

PLAY/ FF

.STOf

REC

I.

RET 3 Q

OPERATING CONTROL SWITCH MATRIX

STROBE 3

Figure 3. A four by four switching matrix on the front panel of the VCR allows control of up tosixteen operator functions. Each strobe output may be routed to any of the return line inputs. Onsome newer machines, operator inputs are handled by a separate microprocessor on the oper-ation board.

sent), tape transport motion is prohibited.CAUTION: With the VCR cover removed,a work bench light may activate the pho-totransistors, even with a cassette inplace, giving a false indication of trouble.

When servicing without a cassette inplace, it may be necessary to block thephototransistors with a small piece oftape. This simulates the presence ofopaque videotape. CAUTION: Do notfastforward or rewind to the end of the tapewith the supply and takeup transistorscovered. Tape damage may result. Don'tforget to remove the tape when service iscompleted.

The SENSOR input on pin 14 is anoth-er safety input which monitors currentflow in the sensor light device. The sen-sor is located on the deck in the center ofthe cassette compartment. If the sensorfails, tape motion is inhibited. If it werenot, tape would run to the end of the leaderand reel drive action would continue. Thiscould result in detachment of the tape endfrom the reel, especially during rewindand fast forward operations.

Pin 15 is the takeup reel pulse input.This signal tells the microprocessor thatthe reel is being driven in the play mode.It is a tape protection function that preventsvideo tape from being spooled out into themechanism if the takeup drive fails.

The takeup reel pulse on newer ma-

chines comes from a sensor under thetakeup reel. It may be an LED/phototran-sistor combination which reflects light offmirrored sections on the bottom of thereel or it may be a Hall device.

Older VCRs use a permanent mag-net/pickup coil arrangement on the me-chanical tape counter. On these machines,belt breakage on the tape counter will pre-vent operation.

Front panel signalsRET 0 through RET 3 (pins 16 through

19) and STROBE 0 through STROBE 3(pins 21 through 24) work together totransfer operator commands from thefront panel to the SYSCON micropro-cessor (Figure 3). Strobes 0 through 3 arefour unique pulse train outputs which arerouted to the switch matrix on the frontpanel. These outputs are present when-ever the VCR is connected to a source ofpower. Return lines 0 through 3 are com-mand inputs to the microprocessor. A fourby four switching matrix allows controlof up to sixteen operator functions (seeFigure 3).

Each strobe output may be routed toany of the return line inputs. On somenewer machines, operator inputs are han-dled by a separate microprocessor on theoperation board. A serial data signal issent from the operation microprocessor to


the SYSCON microprocessor. The over-all operation is the same.

Pin 20 is the electrical ground for themicroprocessor. It may be labeled VSS.

OutputsCM REV, CM FWD and STILL, pins

25, 26 and 27 are control outputs whichtell the capstan motor when and in whichdirection to rotate. These signals are rout-ed to a capstan motor control circuit.

LM REV and LM FWD, pins 29 and30, are output signals which tell the load-ing motor when and in which direction tomove. These signals are routed to a load-ing motor driver circuit.

Pin 31, the CYL CON output, tells thecylinder (video head drum) when to ro-tate. This signal is routed to a cylindermotor driver circuit.

The PWR LED output on pin 32 trans-mits a drive signal to an LED driver onthe front panel to illuminate the "PowerOn" pilot indicator.

The AUDIO MUTE output on pin 33quiets the audio output when no signal is

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present on the video tape. It is generatedby a CTL or control track pulse input tothe SYSCON microprocessor.

The V/T output on pin 34 sends a con-trol signal to the tuner which selects theRF output of the VCR. If the input is high(V), the VCR's tuner is activated and RFoutput is on channel 3 or 4. If the input islow (T NOT), the signal from the RF inputjack is passed through to the RF outputjack and channel selection is made on theTV set.

Pins 36, 37 and 38 are outputs whichtell the capstan drive circuit the properspeed mode. In playback, CTL pulse in-tervals are detected by the microproces-sor and the appropriate speed output pinis activated. In record mode, operatorcommands from the front panel deter-mine the speed signal to be sent to themotor driver circuit. The speeds are: stan-dard play (SP), long play (LP) and superlong play (SLP). Some units may call theSLP mode "EP" or extended play.

SERVICE, on pin 39, is an input usedby technicians to operate the VCR with-out a cassette in place. It is enabled bystrapping the pin to ground.

Pin 40, VDD, is the voltage input to themicroprocessor.

Troubleshooting

Troubleshooting SYSCON problems isstraightforward. Begin by determiningwhich function or functions are not oper-ating properly. Troubleshooting flowcharts are helpful in pinpointing the sig-nals and peripheral circuits which may becausing the problem. If your manual doesnot have flow charts, use the SYSCONblock diagram to analyze circuit function.

Here is the step-by-step troubleshoot-ing process for the problem mentioned atthe beginning of the article. A cassette isplaced into the VCR and nothing hap-pens. If you do not get the proper indica-tion in a particular step, stop and deter-mine the cause. Keep in mind that all ofthe signals must be correct for proper sys-tem operation.

1. Turn the power on and check thefront panel for normal indications (PowerON pilot lit, display panel lit). If indica-tions are abnormal, check the power sup-ply and operation sections.

2. Check the microprocessor supplyvoltage at pin 40 for correct amplitudeand absence of noise or ripple on the line.If the supply voltage is not correct, check

the power supply and decoupling capac-itors on the VDD line.

3. Check pins 1 and 2 for correct clockamplitude and frequency. If incorrect,check the crystal and external compo-nents in the oscillator circuit. If these allcheck out, the internal clock oscillator isdefective.

4. Check the DEW input. It should behigh for normal operation. If it is low, gen-tly apply warm air to the interior of theVCR mechanism to dry it out.

5. Check the POS A through D inputson pins 4 through 7. They should reflectthe "STOP" mode. In this case, pin 4should be low and pins 5 and 6 should behigh. If the position signals are wrong,check the physical position of the mech-anism and the switch. The position switchhas a mechanical alignment indicator whichshould show proper position in the STOPmode. If the alignment is correct, removethe position switch and check continuity.

NOTE: Place a cassette in the VCR andpush it gently into the loading position forthe remainder of the steps.

6. Monitor pin 8, CASS IN. When thecassette is pushed in, pin 8 should go high.If it does not, check the cassette -in switch.

7. Check pin 32, LM FWD. It shouldgo high in response to a high at CASS IN.If it does not, do not assume the micropro-cessor is at fault. Desolder pin 32 and re-check the output signal while it is notloaded. If the indication is now normal,check the driver circuit input for faults.

8. Check the loading motor driver cir-cuit. Motor drive voltage should appearat the output terminals. If it does not, dis-connect the motor from the driver andrecheck the output voltage. If the voltageis then normal, go to the motor check.

9. Check the loading motor. Remove orunplug the power supply wires to themotor. Apply the specified operatingvoltage to the motor from a bench supplyto see if it turns.

The rewards of servicing VCRs

The proliferation of VCRs has madeservicing them bread and butter for manyservice centers. To keep pace, VCR re-pairs must be made by proficient, well -trained technicians.

VCRs are complex systems, but a firmgrasp of some of the basics, along with alogical approach to troubleshooting, willlead to resolution of most problems with-out too much difficulty.


Business suggestions from the bestidea contestResults of a one -hour think tank of independent servicers

By The ES&T Staff

Every year at the National ProfessionalElectronics Conference (NPEC), an an-nual convention and show held by theNational Electronic Service Dealers As-sociation (NESDA), attendees have ameeting at which they share ideas witheach other for improving the operation oftheir service centers.

This meeting is called the "Best IdeaContest." Some of these ideas are actualservicing tips, some suggest ways toimprove business operations, some sug-gest ways to avoid waste or improve cus-tomer relations.

Following is a listing of the best ideasgenerated at the 1993 NPEC, generouslyshared with ES&T readers by the peoplewho generated them.

Best Ideas1. Get the most out of yellow page ad-

vertising by using the yellow page couponsystem and referring to them in your dis-play ads. Gives the prospective client an-other reason to do business with you.Don't refuse outdated coupons, but chal-lenge the client cheerfully to "make up"for the fact that it's outdated by referringtheir friends to your company.

2. Create an "I love me" wall in yourservice center. Put up all training certifi-cates, CET Certificates, awards etc. Thishelps to boost the morale of employees.

3. Develop a team approach to servic-ing. At least three techs per team (teamsof two seem to fail). Reworks can be doneby any team member. This helps every-one pull together and become a more pro-ductive team.

4. To remind members of associationmeetings, supply each member with a cal-endar for the year with all meeting datesstamped on it.

5. Make cards to be put on repairedVCRs during the winter months stating"Cold weather warning." This alertsowners who are picking up repairedVCRs to let their recorders reach roomtemperature before inserting a tape.

6. When tape damage and debris isfound in VCR servicing, use a sign on thedoor of the VCR telling the client to re-place their defective tapes. Include in-structions on how to examine, store, carefor and purchase videotape.

7. Have a calendar printed on the backof your business cards. Gives another rea-son to keep your card.

8. Create a flyer telling of the benefitsof calling a service center that employsCETs. Put your service center name, ad-dress, and phone number at the bottom.This allows for a self-imposed standardand brings a servicer to another level byassociation involvement.

9. Charge a hazardous material dispos-al charge. Five percent of parts billing.

10. Request effective placements ofprint advertisements. Best placement isthe outside half of the page. Study yourmedia buys.

1 1. Try a reverse print ad to draw atten-tion. Use a black background with boldwhite print.

12. Use trade listing in outlying area

phone books. List your company logo incolumn ads.

13. Use a separate phone number totrack Yellow Pages ads in outlying areaphone books to track where phone callsare coming from. Ask your yellow page

salesman to tell you about key call for-warding. This inexpensive method willrequire no added phone lines, but countthe number of incoming calls generatedby a specific ad.

14. Prepare a hardbound service centerbrochure to give to prime clients, retaildealers, bankers; whoever you wish toimpress with the scope and professional-ism of the company. Use color pictures-of your exterior and work areas. Neatnessalways counts.

15. Give dissatisfied clients, upon mak-ing amends, a ten dollar appreciationpostcard coupon to be used for the nexttime they need service. Gives you a sec-ond chance to please them. Confirms theconcept that you truly want to please themand do business with them again.

16. Use a six-inch length of folded ducttape on your test video tapes to stick outof VCRs so the test tapes don't get lost.Apply this tape to the bench area and thefront office test videotapes to avoid leav-ing them in the repaired and tested videorecorders. This works for Nintendo testcartridges and some audio applications.

17. Create an advertisement on the tapedescribed in the item above.

18. Use yellow safety tape on the testtapes above.

19. Print hookup instructions for cli-ents. Place on all outgoing repaired prod-ucts. Be certain to put an advertisement(of what other work you do) with a cou-pon on this instructive flyer.

20. Whenever presenting a bill to aclient, declare: "You must not have a ser-vice contract. I see there is a charge-


would you want to purchase extended ser-vice coverage?"

21. Make a deal with video rental storesto put your coupon with each tape rentalsgoing out, to promote your service. Reci-procate with cleaning clinics at theirvideo stores.

22. If you do a high volume of shipping,charge the client for insurance and put thismoney in a separate account and payclaims yourself instead of paying thepackage delivery company.

23. Spruce up your service center byputting up manufacturers logos, lights,flyers and banners. Many are free fromthe manufacturer-just ask. Some mustbe requested from sales departments.

24. On all VCR repairs, place a cardthat provides details of VCR adjustmentand cleaning entails. A good beginningsample document is provided in the ad-vertisement of test alignment equipmentmanufacturers.

25. Save counter space by mountingcomputer monitors under the countersand the keyboards on drawers. This alsolooks very professional.

26. Update your credit card machine.Use a new scanner that produces the in-voice; some scanners even have an ATMthat can put the money directly into youraccount. Stay in contact with your bankfor new services.

27. Print business cards that have a spot

for your pager number. This is now a wellaccepted modern day contact system.Most clients know how to use pagers.

28. Use a red ink stamp on billings thatimposes a financial penalty if "not paidwithin thirty days." Allow a space for thecutoff date after which a $15.00 latecharge would be imposed. This declaresan anticipation of timely payment with apenalty if delinquent.

29. Generate a postcard that states if theserviced unit is not picked up within twoweeks after notification, a dollar -a -daystorage charge will be levied. Check to besure this is allowed by local ordinances.

30. Use an "extra service performed"checklist sheet and tape it to the repairedunit. Detail cabinet cleaning/inspections,door reseating, antenna rod lubricating, etc.

31. When units are left for over a fewweeks, send a letter requesting ten dollarsfor a disposal fee. This provokes the ac-tion of the owner to either send the moneyor pick up the product.

32. Put a stamp or a card on your invoic-es to proclaim membership in profes-sional organizations-let clients knowyour company is industry alert and a par-ticipating member of an organization.

33. Conduct a free VCR cleaning clin-ic. If you are an independant servicer,work out an agreement to do this at a deal -

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ers store. If you are a servicing dealer, dothis on your sales floor. Focus the sessiontoward working VCRs in need of clean-ing. Give preliminary estimates on anyunit needing repairs. Sell new units, tapesand accessories at this session.

34. Create an employee involvementsuggestion program. Offer rewards from$25 and up depending on how productiveand useful the suggestion.

35. Whenever an ASR (AdditionalService Required) product arrives at thefront counter, have available a red tab toplace prominently on top of the work or-der, to show the client that immediate ser-vice will be performed on their unit. Thisacts as a direct front counter action to con-firm the expedite process to the set owner.

36. On some products you can use a tiermethod for estimates. If the primary esti-mate is turned down, give another esti-mate using generic parts at a lower price.This will often help save the job. Uses thesame concept of generic medicines as acost alternative in health care.

37. Have a system for preapproved esti-mates at the incoming counter. Only callan estimate if it exceeds that amount. Usehistory of product classifications anddominant symptom code as a guide.

38. Establish a "C & L" charge on in-voices-a suggestion was to add $5.00.C & L stands for clean and lubricate. Analternate suggestion: use "C, L & M."This stands for cleaners, lubricants andservice manual.

39. Detail all charges on your serviceinvoice for cleaners, other chemicals, andservice data-this confirms, during taxaudits, that taxes have been paid on allchemical sales, and that therefore, no add-ed vendor sales tax is due on your chem-ical purchases for resale.

40. Add a charge for chemical productsand one for safety and leakage checks.

41. Inventory your investment in ser-vice literature and calculate dollars com-pared to units serviced. Include return oninvestment. Suggestion is to charge a $2.00service literature charge on each invoice.

22 Circle (61) on Reply Card

Test Your Electronics KnowledgeResistors, circuits, thermoelectric effects & more!

By J.A. Sam Wilson. NVA8RMS

Figure A. Can you add a resistor to convertthis circuit into a Wheatstone bridge?

1. Can you add a resistor to convert thecircuit in Figure A into a Wheatstonebridge?

2. A certain LC -tuned circuit passes arange of frequencies I 5KHz wide. It hasa resonant frequency of 500KHz. What isthe Q of the tuned circuit?

3. How many revolutions are there in200n radians?

4. Refer to the circuit in Figure B. Canyou obtain a power supply with a nega-tive output voltage by reversing thediode?

5. The three wheels in Figure C haverubber tires and they are pressed togeth-er. Wheel #1 is the driving wheel. Whichdirection will wheel #3 turn?

6. A robot that looks and acts like ahuman is said to be

7. What is the name for a value that isbeing sensed by a transducer?

8. If you heat one end of a metal rodthere will be a voltage across the rod.

Wilson is the electronics theory consultant for ES&T

Figure B. Can you obtain a power supply with negative output voltage by reversing the diode inthis circu.t?

What is the name for this thermoelectriceffect?

9. What type of radio has a block dia-gram like the one shown in Figure D?

10. Which of the following is a char-acteristic of all tunnel diodes?

A. very high forward currentB. tunnel diodes are no longer availableC. used only as a video detectorD. has a characteristic curve with a neg-

ative resistance region.

(Answers on page 67)

Figure C. If wheel #1 is the driving wheel in this figure, in which direction will wheel #3 turn?

Figure D. What type of radio has a block diagram like this?


What Do You Know About Electronics?

Servo systemsBy J.A. Sam Wilson, WA8RMS

Every VCR and camcorder contains aservo system to control tape speed. Athorough understanding of these productsrequires a working knowledge of servos.For that reason, we'll be discussing ser-vos in depth in this column.

By way of review, Figure I shows anexample of a phase -locked loop. It is oneform of a servo system. Remember that anyclosed -loop, negative -feedback system isa form of servo. The loop in Figure 1comes close to the type of servos used ina VCR. In fact, with a little modificationit could be used for motor speed control.

The system shown in Figure 2 is morelike the way a servo is actually construct-ed. The output signal from the motorspeed sensor may not require amplifica-tion. If it does, the amplifier will likely bein an integrated circuit.

There is no need for a VCO (voltage -controlled oscillator) in the motor speedcontrol system because the output pulsesfrom the motor speed sensor are easilymatched with a reference.

The low-pass filter is not needed be-cause the motor is not sensitive to highfrequencies coming from the comparator.In fact, those high frequencies probablydon't exist anyway.

After you take out all of that stuff fromthe phase locked loop you have a motorspeed control like the ones actually usedin a video cassette recorder. We are backto Figure 2. That could be a speed controlfor either the capstan motor or for thedrum motor.

Let's look at each of the blocks and seehow the signals are obtained.

The motor speed sensorA popular way to sense the speed is to

embed a magnet in the rotating part of themotor. For drum speed control, the mag-net is located in the lower part of the drum,as shown in Figure 3. (This illustrationwas drawn over from a 1992 J.C. PenneyModel 6219 manual).

The speed sensor is often a Hall device.

Wilson is the electronics theory consultant for ES&T

Figure 1. A phase -locked loop is one example of a servo system.

Figure 4 reviews the principle involved.With no magnetic field the electron cur-rent through the device is evenly distrib-uted throughout the conductive element,so there is no voltage across the sides.

When there is a magnetic field throughthe conductive element the electron cur-rent is deflected so there are more elec-trons on one side of the conductor. Thatresults in an output voltage.

Therefore, every time the magnet pass-es the Hall device there is an output volt-age in the form of a pulse. Instead of aHall device it is possible to sense the mag-netic field with a coil. A head from an audiotape recorder would work in this application.

In the previous issue we looked at somesensors that would work very well. Thebottom line is this: There must be somemethod of sensing the motor speed! Thespeed sensor is what I call a touch point.It is a place where you can use your scopeprobe to look into the closed loop to seehow things are going.

I have suggested in past issues that youcould disable this sensor and substitute apulse of your own. Manufacturers usual-ly don't mention that possibility in theirtroubleshooting manuals. One reason isthat you have to be very careful not to ex-ceed the amplitude of the normal sensorpulse. That pulse is often delivered to an

REF

VOLTAGE OR PHASFCOMPARATOR

POWERAMP _IFIER

AMPLIFIEARAND SHAPER

MOTOR TRANSDUCER

Figure 2. This system is more like the way a servo is actually constructed.


CAPSTAN

UP -%me/)

CAPSTAN FRED OUTPUT

CAPSTAN CONTROL

DRUM CONTROL

DRUM FREQUENCY OUTPUT

DRUM PHASECONTROL OUTPUT

Figure 3. One way to sense motor speed is to embed a magnet in the rotating part of the motorFor drum speed control, the magnet is located in the lower part of the drum.

integrated circuit and you don't want tooverpower one of those guys-even if itis momentary and accidental.

There is another problem that youmight run into. You may not be able to getto that sensor. You can, however, usuallyget to the point where the speed sensorsignal goes.) I am not saying to disregardthe manufacturer's suggested trouble-shooting procedure, but, I know techni-

cians with much experience and good testequipment who use their own procedurein some applications.

ComparatorThere must be a place in the servo sys-

tem where the speed sense signal from themotor is compared with a reference. In aprevious issue I used a crystal oscillatoras a reference. In VCR servo systems the

Figure 4. A Hall -effect device, whose principle is shown here, is often used as a speed sensorin VCR motor speed applications.

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100 -

90

70.

60-

50

40.

30.

20.

10.

0

2 3

TIME CONSTANTS

4 5

(A)

3.58MHz frequency may be counteddown and used for comparison with themotor speed pulses. Another possibilityis to use a pulse in the video signal-likethe vertical sync pulse.

Figure 5. You can construct a capacitor charge/discharge curveof this circuit (B) using this set of coordinate axes (A) and a cal-culator, as described in the text.

So, you are looking for two pulses intothe comparator: speed pulses and a refer-ence signal. The location of those two sig-nals are touchpoints.

Don't overlook the possibility that the

100-

90-

80-

70-

60-

50-

40

30-

20

10'"

0

TABLE I

LEGEND: CHARGING CAPACITOR

TIMECONSTANT

% OF MAXIMUMVOLTAGE

1 63.2%

2 86.5%

3 95.0%

4 98.2%

5 99.3%

1 2 3 4 5

Figure 6. Using a calculator to compute the various points on the time -constant curve results inthis graph.

speed pulses are rectified and the result-ing dc is used for comparison. The speedpulses can also be shaped and used inanother form. But, when you get donewith all of the possibilities, you are stilllooking for two signals or voltages. If youcan't find either one, you are in the vicin-ity of the problem.

Power amplifierAt the point where the signals are com-

pared there must be an output control sig-nal-one that is produced in the com-parator. That signal will change whenthere is any variation in the motor speed.Whatever the reason for that change, thecomparator has to produce an output sig-nal that will get the motor back to the cor-rect speed.

If you are innovative and resourcefulyou might slow the drum or capstan witha very light touch and watch the com-parator output.

That output should change when thefriction is added.

In some cases, that output signal goesto an analog amplifier that can deliverenough power to operate the motor. Pow-er amplifiers are always to be looked atwith suspicion. Even if it is located insidean integrated circuit, it has to deliver anoutput signal to control the motor speed.

That is another touchpoint.To summarize, you can use the manu-

facturer's test procedure to locate trouble


in the servo system. There are also cer-tain touchpoints where you can look atsignals. Using those touchpoints shouldhelp in deciding the source of the problem.

There will be further discussion of ser-vos in future installments of "What DoYou Know About Electronics?"

Piecewise approach totime constant problems

So far we have looked at time constantproblems using a mathematical approachand a graphical approach. In this articlewe will extend the graphical approach. Ithink you will find it interesting to seehow this method makes it possible tosolve all of the time constant problems inthe FCC General Radio Operator License(GROL) exam.

The GROL exam is the new licensingtest that takes the place of the long-stand-ing FCC license exam.

The graphical approach to solving timeconstant problems was previously givenin this column. It required a universal timeconstant curve as a starting point. Thatbrings up the next question: what to do ifyou can't lay your hands on the universaltime constant curve?

The answer is that you can make oneby making graphical coordinates andusing a simple calculator. Let's go throughthe procedure together. Refer to Figure 5.The horizontal axis is used for time con-stants and the vertical axis represents thepercent value of the dc voltage. For con -

100

90

80-

70

60.

50-

40-

30.

20.

1C

TABLE II

LEGEND: DISCHARGING CAPACITOR

TIMECONSTANT

% OF MAXIMUMVOLTAGE

1 36.8%

2 13.5%

3 5.0%

4 1.83%

5 0.7%

2 3

TIME CONSTANTS

4 5

Figure 7. The voltage across a capacitor as it discharges varies like this.

venience, we can say that the vertical axisis marked for 100V. However, it can alsorepresent 100% of any voltage.

Figure 5 also shows the circuit used todescribe what is happening. When theswitch is turned to position 'A,' capaci-tor C begins to charge through resistor`R'. You know that at the end of one time

constant the voltage across the capacitorwill be 63.2V.

When the switch is in position B thecharged capacitor discharges through theresistor. You know that the voltage acrossthe capacitor will drop to 36.8% of the orig-inal full -charge voltage in one time constant.

Our discussion starts with the switch

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turned to position A. From the momentthe switch is turned to position A until themarking for the first time constant, the ca-pacitor charges to 63.2% of applied voltage.

During the period betwen the first andsecond time constant, the voltage will in-crease another 63.2 percent of the remain-ing voltage. In other words, at the firsttime constant marking, the voltage willcharge to 63.2V. During the next timeconstant period the capacitor will chargeto 63.2% of the remaining voltage (thatis, it charges to 63.2% of 26.8V betweenthe first and second time constants). Infact, during each time constant period, thecapacitor charges to 63.2% of the remain-ing voltage.

Taking that into consideration, I havemade a simple step-by-step procedure forplotting the points on the time constantcurve for the charging capacitor. Table 1(Figure 6) shows the result of each step.

Step I: Voltage of the previous step:V.

Step 2: Subtract the voltage in Step 1from 100: V.

Step 3: Multiply the voltage in Step 2

by 0.632: V.

Step 4: Add the voltage in Step 3 to thevoltage in Step 1.

The voltage in Step 4 is the voltagemarked on the next time constant line.

Enter the voltage in Step 4 into the tableand the graph. Here are a few examples:

At the first time constant:Step 1: Voltage of the previous step:

0 V.

Step2: Subtract the voltage in Step 1from 100: 100 V.

Step3: Multiply the voltage in Step 2by 0.632: 63.2 V.

Step 4: Add the voltage in Step 3 to thevoltage in Step I 63.2 V.

The result of Step 4 is the voltage at thefirst time constant line.

For the voltage at the second time con-stant line:

Step I: Voltage of the previous step:63.2 V.

Step 2: Subtract the voltage in Step 1from 100: 36.8 V.

Step3: Multiply the voltage in Step 2

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by 0.632: 23.3 V.

Step 4: Add the voltage in Step 3 to thevoltage in Step 1 86.5 V.

The result of Step 4 is the voltage at thesecond time constant line.

For the voltage at the third time con-stant line:

Step 1: Voltage of the previous step:86.5 V.

Step 2: Subtract the voltage in Step 1from 100: 13.5 V.

Step3: Multiply the voltage in Step 2by 0.632: 8.56 V.

Step 4: Add the voltage in Step 3 to thevoltage in Step 1: 95 V.

The result of Step 4 is the voltage at thethird time constant line.

Continue with the fourth and fifth val-ues. Then, connect the dots on the graphand you will have a piecewise graph ofthe time constant. The final result isshown in Figure 6.

To make the discharge curve you sim-ply take 36.8% of the voltage at the pre-vious step. See figure 7. For example, onthe discharge curve the voltage at the firstline is 100V.

Take 36.8% of that to get the voltage atone time constant. That gives you a volt-age of 36.8V (see Figure 7, Table II). Forthe second point you take 36.8% of thevoltage at the first step:

0.368 x 36.8V = 13.5V

For the third point you take 36.8% ofthe voltage at the second step:

0.368 x 13.5V = 5V

Continue to do that until you have com-pleted Table II (Figure 7).

Readers with a flair for drawing cansmooth out the lines to get a reasonablyclose time constant curve.

Now you can solve any time constantcurve graphically. To solve problems onthe FCC test, however. you do not needthe time constant cure! All you reallyneed is the table. In fact, I will go one stepfurther. You don't even need the table ifyou remember how you got the values inthe table!

In the next issue of ES&T, I will con-tinue this discussion.


LiteratureEnvironmentally -safer

chemical productsCAIG introduces a new line of environ-

mentally -safer products in its new 1994catalog. These high-performance prod-ucts can eliminate the need for repeatedcleaning with ozone -depleting or hazard-ous cleaning and lubricating products.Many aerosols are completely safe for theenvironment, but recognizing that manyaerosol packages have no safe alterna-tives, CAIG offers a complete line ofthese concentrated formulations usingnon -aerosol applicators (wipes, pens,precision needle & syringe dispensers,etc.) for the aerosol -sensitive customers.Products include; connector/contact de -oxidizers, conditioners and preservatives,precision lubricants, anti -static products,solvents, pastes, cutting oils and manyother industrial chemical products.


Test equipment catalogPrint Products International just re-

leased their 84 -page, 1994 discount testand measurement equipment catalog. Thecompletely revised catalog is 30% largerthan the 1993 edition and features newlines of equipment from Stanford Re-search Systems, N.T.E., Yokogawa, Data-com, Goldstar, Instek, Sadelco and more.Products in the 20 new pages includespectrum analyzers, signal strength me-ters, logic analyzers, protocol analyzers,digital and analog oscilloscopes, semi-conductors, and surface mount solder-ing/desoldering equipment.


Guide to selection of soldersand chemicals

A new six -page, four-color brochurefrom Multicore Solders provides a quickreference guide to the company's com-plete product line.

Among the categories of products cov-ered are: cored solder wires, solderingfluxes, coatings, wave and static bath sol-ders, solder creams, SMD adhesives,cleaning liquids, specialty products, pro-totype production equipment and processcontrol instruments. A variety of productswithin each category are described withgeneral applications for each included.


Catalog of new toolsA new 80 -page, full -color tool catalog

is now available from Time Motion Tools.It includes field service tools and tool kitsfor the electronic professional.

A new expanded section featuring light-ing and magnification equipment has beenadded to this easy -to -use catalog whichalso features computer, telecommunica-tions, LAN, test and measurement equip-ment and maintenance and repair tools.


Literature sheet describespower supplies

Coupling the ease of keypad data entrywith four -digit LCD readout accuracy arethe five 300 Series of linear programma-ble power supplies from American Reli-ance Inc. The top -of -the -line LPS-305 is atriple output supply with RS -232 interface.

These user-friendly single and tripleoutput supplies, with output power rang-ing from 30W to 165W are described ina two -page literature sheet.

The units feature microprocessor con-trol; digital programming and readback:keypad data entry; power -off memory;voltage and current slew function; lowPARD/noise and ripple; superior line andload regulation: output enable/disable;and two year warranty. Current accuracyon all units is ±0.5% of reading + five dig-its. Voltage accuracy is ±0.2% of reading+ two digits. Setting resolution is 1mA;line regulation, 15mA; and load regula-tion 5mA.

Power -off memory of all units retainsboth voltage and current settings. An out-

put enable/disable function allows theuser to safely disable the output withoutchanging the voltage or current settings.Status annunciators on the LCD panel areupdated continuously to inform the userof the power supply's status at all times.


Application/selection guides forbenchtop cleaners

A series of application and selectionguides outlining the benefits of the latestalternative benchtop cleaners for elec-tronic circuitry is now available fromMicro Care Corp.

The new literature provides inputs onmajor brand chemicals and consists of athree -fold pamphlet entitled "StraightTalk About Alternative Cleaners" as wellas two single -sheet handouts featuringeasy -to -read charts.

The "Straight Talk" pamphlet discuss-es the whys and wherefores of non-CFCcleaners at the workbench and specific-ally details the application and effect ofthe new HCFC cleaners, PFC cleaners, al-cohol and deionized water, plus severalnew chemistries formulated to meet thelatest environmental regulations.

The single page "Product Selection"guide discusses the use and effect of mild,moderately strong and highly activecleaners along with their abilities to sub-stitute for old-style solvents.

The companion "Technical Applica-tions" bulletin outlines critical handlingcharacteristics of "planet -safe" chemicalsand charts product characteristics such asstrength, health, safety, and environmenteffects and brief comparative summaries.


Product catalogGalco Industrial Electronics has re-

leased an updated, easy -to -use. productcatalog which contains over 260,000items. These items are easily locatedthrough the use of either the product indexor the manufacturer index. In addition.each section has an individual index forquick referencing.

The catalog contains technical specifi-cations and application information. Inaddition to what is available in the cata-log, the company's sales staff can assistthe customer in identifying and locatingthe hard -to -find parts.



* * * DISTRIBUTORS' SHOWCASE * * *When a service technician sits down

to perform a diagnosis on a set thathas malfunctioned, in many instancesit becomes a major effort to locate ser-vice information. When a techniciancompletes a diagnosis and determinesthe cause of a problem in a TV, VCRor other consumer electronics product,often that's merely the prelude to theserious problem of locating a replace-ment part that will restore the productto proper operation.

In years past, finding service infor-mation and replacement parts was notas much of a problem as it is today.There was only a relative handful ofproducts and manufacturers, andmost service information and replace-ment components were readily identi-fiable and obtainable. Nowadays,obscure products from hard to findmanufacturers are increasingly likelyto be brought in for service, and locat-ing service information and parts mayrequire detective ability and tenacity.

Fortunately, there are a number oforganizations that can assist a techni-cian in the search. A well -organized,well -stocked distributor is one agencythat can provide a great deal of assis-tance in finding the necessary infor-mation and products. Because a gooddistributor can provide important help,whether you do almost all of your busi-ness with a local distributor or a mailorder firm, or some combination of thetwo, it is prudent to choose carefullythe distributor(s) with whom you dobusiness.

Similar but differentJust as with any other kind of selling

organization, you'll find many similari-ties and many differences among dis-tributors. Most distributors are wellorganized and well stocked, can helpyou with special requirements, andhave a research department to helpyou find the part you need; some arenot. Some mail-order distributors canaccept your orders in a variety of waysincluding mail, telephone (some with800 numbers), fax, etc.; some cannot.Some distributors charge a reason-able fee for shipping and handling;some will charge you what you will con-clude is an exorbitant amount. Somedistributors will send your order rightaway even before your check clears,

some will wait until your check clears,and some will keep your money wellbeyond the point when they shouldhave shipped your order.

Some variables to considerMost people are careful shoppers

when it comes to buying consumergoods. It pays to shop just as careful-ly when choosing a distributor.

Here are some of the factors youshould consider when settling on a dis-tributor. Some apply only to the localdistributor, and some apply only to mailorder, but it would be a good idea tokeep them in mind any time you'rethinking about doing business with anew firm.

Do the facilities and/or literaturegive the impression of competenceand order?

Do prices seem reasonable and inline with what other companiescharge?

Are most items in stock, or willmany have to be back ordered?

Does the distributor offer a broadline of products, or will you have to findother sources of supply for many ofyour needs?

Does the distributor specialize inany particular kinds of products thatyou typically order?

What kind of payment options areavailable: Open order account, creditcard, COD, check, etc.?

How soon after receipt will yourorder ship?

Is there a shipping surcharge, or ahandling charge?

Does the company list a toll -freenumber?

Are such ordering options as fax,and telex available? How about suchcomputer ordering options as MCIMail, Compuserve, and EasyLink?

What is the return policy? Are all policies well documented,

or do you have to guess at them? Ordo they seem to differ depending onwhim?

What kind of warranty, if any, doesthe distributor offer?

Does the distributor publish a cat-alog? If so, is it clear and easy to under-stand?

Is there a minimum order amount?If so, is it reasonable?

What kind of shipping options are

available: mail, UPS, Federal Express,etc.?

What kind of special services, suchas assembling cables, etc. does heoffer?

What research services are avail-able to help you to find the part youneed?

These questions can beimportant

Some of these questions may notseem important, but from what wehave learned from some of our read-ers, they may be very important. Forexample, we learned from one of ourreaders that one mail order companymade a regular practice of chargingunnecessarily high shipping charges.

Another practice that some distribu-tors indulge in is to hold shipment ofproducts for some time after the pur-chaser's check has cleared. This givesthe distributor a nice little interest- freeloan between the time the check clearsand the time he decides to ship themerchandise. This is not necessary.Some companies ship the productimmediately after receiving an order.

Don't forget to ask about restockingfees. Some distributors charge a re-stocking fee even when they wereresponsible for shipping the incorrectproduct in the first place

Let the buyer bewareMost replacement parts distributors

are hard-working, well -organized, eth-ical companies, who will make everyeffort to help you obtain the correctreplacement for a faulty component.Some are less ethical in their prac-tices. It's not always easy to locate thegood ones and avoid the ones that willgive you problems.

When you're considering orderingproducts from a new distributor, itmight be wise to start out with a smallorder and see what kind of treatmentyou get. If the service is good, youmight gradually increase the size ofyour order and gradually build up aclose working relationship.

If the service you receive is not whatyou'd like, try someone else. It's yourbusiness that will suffer if you don't getwhat you order when you need it, or ifyou're hit with exorbitant freightcharges that you have to pass alongto your customer.


* * * DISTRIBUTORS' SHOWCASE * * *

Philips Technical Training401 East Old Andrew Johnson HighwayJefferson City, TN 37760Phone: 615-475-0044FAX: 615-475-0221

Philips Technical Training is one ofthe many departments that make upPhilips Service Company. Our prima-ry responsibility is to provide for thetraining needs of all servicers, includ-ing Philips Authorized Servicers. Weproduce various forms of trainingmaterials, such as hands-on techni-cal training books, and conduct train-ing classes all over the country. Thelocations of these classes are specif-ically chosen for easy access of ser-vice companies.

Hands-on trainingOur hands-on training is the most

comprehensive service training avail-able today, teaching both circuit oper-ation and troubleshooting! PhilipsTechnical Training has been voted"Number One in Technical Training"for eight years running by servicersattending these classes!

Communication with servicers isthe key to our success. Servicersattending our classes keep usinformed of problems being faced ona daily basis, as well as subject mate-

rial that is of interest to them. We takethis information and structure ourtraining materials to better fit theirneeds. If there is a product servicerswould like made available to them, tohelp them in their profitability and effi-ciency, we do our best to make it avail-able.

Light boxesWe learned from these training

meetings that there was a need for aninexpensive light box with charts. Sowe built our own, and are currentlyselling it at a price that makes cam-era repair more profitable. It is nowmuch more cost-effective for ser-vicers to make the transition fromVCR to camera repair.

Computer softwareServicers informed us of a need for

a computer program that would giveinstant access to part numbers, sub-stitute numbers, dealer cost, dudprices, descriptions, and availability.We immediately began working todevelop a program. Today, it is avail-able, and includes over 260,000 part

numbers. It includes generic andPhilips part numbers, as well as allother requested information.

Video tapeAs a result of requests for more

videotapes covering electronicsrepair, we are offering videos cover-ing VCR mechanics, CD repair,switching mode power supply ser-vice service tips review, and cam-eras. In fact, the demand was so highwe decided to expand our video pro-duction facilities to triple cur output ofvideos by the end of 1993!

Highest qualityPhilips Technical Training is com-

mitted to providing total customer sat-isfaction. We are also committed toproducing the highest quality of train-ing in the industry. Our hands-onclasses, training books, tapes, andsoftware are all accompanied by aqualty survey card. This survey isused to constantly check the qualityof our products as seen by the tech-nician. Quality and effective trainingare of the highest importance to us!

Order your catalogA free catalog, containing descrip-

tions of all products and training mate-rials offered, is published annually byPhilips. You can get your catalog bycalling the Technical Training depart-ment at 615-475-0044.


* * * DISTRIBUTORS' SHOWCASE * * *PTS Corporation5233 Highway 37 South PO Box 272Bloomington, IN 47402-0272Phone: 800-844-7871FAX: 800-844-3291

PTS Electronics has been the electronics ser-vice dealers best friend by providing fastdependable service to thousands of servicedealers for more than 25 years.

PTS is the nation's largest single source forall major brands of television tuners and TVmain boards. Brands such as RCA, Zenith, GE,and NAP are available at substantial savingsof up to 60% when compared to OEM directreplacements.

Recently, PTS has updated and expandedour offering of PC boards for Sharp Microwaveovens. Since 1979 PTS has been involved in therepair of Microwave PC boards. In the comingmonths, we will be adding other manufacturersto our line of Microwave PC boards.

Rebuilding is what we do bestPTS began in 1967 remanufacturing televi-

sion tuners, and now remanufactures televisionmain boards, satellite receivers, completechassis, projection set boards, computer mon-itors and microwave oven panels.

Specialization has made PTS the largest andmost efficient independent electronics rebuilderin the world. Maximum use of availableresources and skill has made PTS the leader in

electronics rebuilding, with the ability to adapt tonew technologies and advance into new mar-kets according to customer needs.

PTS specializes in rebuilding/remanufactur-ing electronic timing devices, modular circuits,and electronic tuners and main boards. PTS cur-rently maintains contracts with major manufac-turers in a variety of industries including whitegoods, television, computer, automotive, med-ical and various government agencies.

Currently, PTS rebuilds over a million ana-log and digital products, components and sub-assemblies each year.

Dedicated to customer satisfactionAt PTS, just providing our customers with

high quality products and services is notenough. Our goal is total, unconditional cus-tomer satisfaction. Since 1967, PTS has beenthe world's leading independent electronicsrebuilder and parts supplier. We provide theelectronics industry with quality repair servicesand parts. We have worked with leading man-ufacturers to develop service programs foremerging technologies. We've seen a lot ofchanges over the years, but there's one thingthat hasn't changed. That's the value and qual-

ity of our products and service programs.You don't just become an industry leader

overnight. It takes several years of experienceand dedication to achieve excellence. It alsotakes a real commitment to training as well asstate-of-the-art diagnostic and service equip-ment. PTS has the commitment.

Our staff are seasoned veterans who putthemselves in the customer's shoes. Theyknow how to listen and respond to a customer'sneeds. Each call is evaluated very carefully,and the response is always supportive andhelpful. When you use PTS products and ser-vices, you become a part of our family. We'll gothat extra mile to make sure you're happy andsatisfied. When you call PTS, we really meanit when we say "PTS Electronics, how may wehelp you?"

PTS maintains a state-of-the-art computersystem that allows instant response to yourorder inquiries. Our staff of customer servicerepresentatives are very knowledgeable of ourproducts and services, and can help ensurethat you get the part you really need.

PTS carries thousands of different parts forvirtually every major manufacturer, and hasmore than 3 million parts in stock.

With a 40,000 square foot corporate facility,PTS employs more than 175 technical person-nel and support staff. Branch operations arelocated in Longview, TX and Arvada, CO.There are over 300 individual test positions forlive testing of television tuners and mainboards.PTS keeps thousands of tuners and main -boards in stock for immediate shipment andalso services all major brands.

So, call today to place your order and ask forour free price guide or for more information.

SERVICE PROBLEM?PTS has the solution!OTC glariirran;sc VII1611,

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44 Electronic Servicing & Technology April 1994Circle (47) on Reply Card


Herman Electronics1365 N.W. 23rd St.Miami, FL 33142Phone: 800-938-4376FAX: 305-634-6247

Herman Electronics is a diverse, full -linedistributor of everything in electronics. Thecompany, now over 40 years old, has clear-ly established itself as one of the best inthe industry by providing quality productsto all phases of the electronics industry.

Herman Electronics' supplies full "in -stock" deliveries from their vast assort-ment of semiconductors, batteries, con-nectors, wire and cable. They also spe-cialize in test equipment and tools fromsuch quality companies as B&K,Wavetek/Beckman, Fluke, Goldstar, andHitachi. Herman offers a huge selectionof soldering and desoldering equipmentfrom Hakko and Weller. Essentially, theyare a "one -stop" supplier for servicing per-sonnel.

The heartbeat of the business lies in theOEM parts department. While servicingthe industry for over three decades,Herman Electronics has acquired many ofthe major OEM parts lines in order to pro-

vide more efficient and cost effective ser-vice to you. Herman Electronics is a fac-tory authorized original replacement partsand accessory distributor for Sony, GE,Samsung, Panasonic, RCA. Quasar,Casio, Technics, and Toshiba. Stockingone of the largest and most comprehen-sive inventories, we fill over 80% of ourorders from our 25,000 stocking items andguarantee two-day service to your door onall in -stock orders placed before 2:00 p.m.(EST).

Herman Electronics is able to provide avariety of customer support services as aresult of the company's commitment tomaintaining a standard of excellence inserving customers. We have several ser-vice representatives to serve your needsfrom 8:30 a.m. to 5:30 p.m. (EST) Mondaythrough Friday and from 8:30 to 12:30 onSaturday. Whether your request is for pric-ing, stock availability, or research, thecompany's toll -free lines and 24 -hour faxlines are readily available to fulfill all of yourrequests. Furthermore, the company guar-antees to fill your research requests with-in three hours and generates computerizedbackorder reports with ETAs to keep youabreast of your backordered items.

The company ph, itself on being flex-

ible and accommodating to its customers'requests. "We realize there are many gooddistributors throughout the country" saysJeffrey A. Wolf, Vice -President and son ofone of the company's founders. "It is ourjob to be better by taking that extra step ingiving our customers professional person-alized service. Our industry has clearlybecome service oriented. Therefore, weare dedicated to maintaining a standard ofexcellence in serving our clientele."

The fringe benefits provided by Hermanare several resulting in service and cus-tomer satisfaction second to none. All out-of-state orders are shipped UPS 2nd dayair at no extra charge. Several methodsof payment are available including a net30 day open account, COD, and Visa,MasterCard, and American Express. Toaccommodate the west coast, and after-hours orders and requests, HermanElectronics' has a sophisticated electron-ic phone ordering system to accommo-date you 24 hours a day, seven days aweek.

If you have not given Herman Electron-ics a try, please do so, you will be glad youdid. Call now! Herman Electronics-ourparts are factory original and our service isstate-of-the-art.

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800 938 4376 305'634* 6247Your Authorized Parts Distributor for: SONY PANASONIC TOSHIBA SAMSUNG RCA/GE


* * * DISTRIBUTORS' SHOWCASE * * *Projector -Recorder Belt Corp.PO Box 176Whitewater, WI 53190-0176Phone: 1-414-473-2151FAX: 1-414-473-4727

Projector -Recorder Belt Corp. (PRB)has been the nation's leading wholesalesupplier of replacement belts and parts forthe electronic industry for over 36 years.To support and enhance the sale of elec-tronic replacement belts and parts, PRBbegan publishing our own CROSS REF-ERENCE BELT GUIDE in 1970. We feelour customers deserve the time, energy,and money we have invested every yearsince to improve this excellent resource.This year the new PC CROSS GUIDEallows the user to merely enter the spec-ifications of their original belt and instant-ly obtain all the suggested PRB replace-ment belts. With easy -to -follow, menus,finding your replacement belt or part hasnever been easier or faster. In addition,we've added new listings of many R.F.

Modulators and Sensing Lamps. The PRBPC CROSS GUIDE will save you time anddisk space.

Both the PC and Book Format versionof the '94 PRB COMPREHENSIVE BELT& VCR PARTS CROSS REFERENCEGUIDE feature detailed information onreplacement parts for VCRs, Cam-corders, Cassettes, Compact Discs,Answering Machines, Car Stereos ... andReplacement Belts for Tape Recorders,Turntables, AudioNisual Equipment andOffice Machines. The Cross Guide lists amajority of the mechanical parts BY MAN-UFACTURER MAKE AND MODEL . . .

and is crossed to the recommended PRBLine Replacement Part.

PRB is also pleased to offer "Inner -Works. . .VCR Mechanical Replacement

Booklets." The InnerWorks Series coversa wide variety of VCR makes and models.The booklets include easy -to -followmechanical drawings, as well as a com-plete listing of all mechanical parts andassemblies.

InnerWorks Booklets are arranged andgrouped in families so YOU can:

Economically obtain the informationyou need . . . each booklet providesdetailed data for approximately 15-20VCR models of a particular manufacturer.

Easily solve VCR failures . . . since80% of them are due to mechanical partsmalfunction.

Learn how many different models andmanufacturers use the same parts.

Throughout our many years of servingthe electronic industry PRB has alwaysput our customers first. Satisfying them isour goal. Our in-house staff of profes-sionals all work hard to provide the bestpossible products and superior service.The PRB LINE offers . . . the products . .

. the quality .. . the service . .. the prices

. . . you can depend on. For completedetails just call 1-414-473-2151.

I[PERIIA STEP AHEAD WITH 1,11011QUALITY PRODUCTS & SERVICE YOU CAN DEPEND ON . .

BELTS BELT KITS VCR PARTS & ACCESSORIES VIDEO INSTRUCTION TAPES LAMPS NEEDLES

PRECISION TOOLS ROLLERS, WHEELS ADHESIVE BUMPERS WHEEL REBUILDING SERVICE

RESOURCE MATERIALS THAT MAKE YOUR JOBEASIER AND MORE PROFITABLE . . .

PC CROSS GUIDE* . justenter your belt specifications andinstantly see all the suggestedPRB Replacement Belts. The PRB CROSS GUIDE software runs in MS-DOS on any

IBM PC or compatible with 640K of RAM, a small harddrive, and a 5 1/4' or 3 1/2* floppy drive. PRB's databaseoccupies only 1.5 Mbytes of hard disk space when loadedMS-DOS is a registered trademark of Microsoft Corporation.IBM is a registered trademark of International BusinessMachines.

InnerWorks VCR MECHANICALREPLACEMENT BOOKLETS

Stay a step ahead with the PRB LINE. Call yourlocal distributor for complete details.

See us at EDS Booths #3402 & #3404

MEASUR-A-BELT II VIDEO TIRE SIZING CHART VIDEO PRESSURE ROLLER

GAUGE . . . our handy NEWgauge lets you easily measure yourpressure roller's outside diameter,height and inside diameter of thebearing.

NOTE: See editorial copy above for details on the PCCROSS GUIDE and INNERWORKS BOOKLETS.

PROJECTOR -RECORDER BELT CORP.P. 0. Box 176 Whitewater, Wisconsin 53190-0176



Print Products International8931 Brookville Rd.Silver Spring, MD 20910Phone: 800-638-2020Fax: 800-545-0058

Print Products International is a pre-mier distributor of equipment, toolsand supplies for electronic mainte-nance and service. Print carries suchlines as Pace desoldering, solderingand surface mount systems, Leader,Hitachi, B&K, Kenwood, Simpson,Beckman, Triplett, Global Specialties,and Hameg test equipment, as well asbrand name tools for field service anddepot repair.

Print lives up to its logo "we makeordering simple." With our friendlystaff, toll -free phone and fax, huge in-ventory, and quick processing of

orders, it is no wonder that Print hasbecome the "source" for electronic testequipment.

Due to our huge buying power, Printis able to claim that we are the mostcompetitively priced equipment dis-tributor in the country. Prirt buys inlarge quantities, and passes thesesavings on to their customers. As oursales staff says, "If you didn't buy it atPrint, you've paid too much!" Becauseof this buying power, Print sub -distrib-utes equipment to other distributors.

Print accepts VISA, Mastercard,American Express, and COD orders.

Open accounts are available to ratedfirms. Print will ship your order UPSGround, UPS Blue, UPS Red, FederalExpress, or whichever carrier yourequest. A 10 -day trial is available onall equipment.

Remember, when you need testequipment-think Print! "We makeordering simple."

A toll -free phone 800-638-2020 andtoll -free fax 800-545-0058 are avail-able for your convenience. Pleasecontact us for our free catalog.

Products International

LOWEST SCOPE PRICESGUARANTEED!!!

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SALE $389.95

NEM 84 PAGE CATALOG!!!Call Today For Your FREE Copy

Of The 1994 Print Test

Products International Equipment Catalog!

8931 BROOKVILLE ROAD, SILVER SPRING, MD 20910 1-800-638-2020 * FAX 11-800-545-0058

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Tritronics, Inc.1306 Continental DriveAbingdon, MD 21009-2334Phone: 410-679-6688FAX: 1-410-676-76581-800-888-FAXD

Tritronics, Inc. is a family owned andoperated parts distributor, which has beenin business since 1975. Our specialty hasbeen supplying exact replacement partsto the electronic service industry. In thepast year, we have branched out, and nowoffer several quality lines of generalreplacement parts through a catalog andmonthly special fliers.

Tritronics' goal is to provide timely andefficient service for their customers. Toachieve this, they provide the followingservices:

1. Orders received by 3:00 p.m. E.S.T.are shipped that day.

2. Stock over 45,000 line items, over3,000,000 parts.

3. Initial shipments are 85% filled.4. Price and availability is provided on

toll -free numbers for common parts bydescription and by part number. InMaryland call 1-800-638-3328 or FAX 1-800-888-3293 and in Florida call 1-800-365-8030 or FAX 1-800-999-3293.

5. As of April 1, 1993, Tritronics, Inc. isa Premier distributor for RCA, GE, andProscan, offering prompt shipments and"DDS" to help improve your "QOS!"

6. Dragnet, an on-line ordering system,allows easy access to information on over1.5 million parts, prices, inventory, sub-stitutions and common parts by moceland description.

Tritronics is committed to supporting theindependent electronic service industry.Our support has included being a foundingmember of NESDA affiliate ChesapeakeElectronics Association; cosponsoring a

membership drive with NESDA; and sup-porting various local organizations byadvertising in trade journals, sponsoringand participating in special events.

Setting our goals high has paid off forTritronics' customers as well: two of thethree Sharp Servicers who won vans in1992 and two of three Sharp Servicerswho won trips to Japan in 1993, purchasedtheir parts from Tritronics. The CEO,Roger Williams, won NESDA's regionalFriend of Service Award in 1991, and thecompany also garnered several perfor-mance awards from Matsushita ServiceCompany and Sharp Electronics Corp.

Tritronics has a full staff in both our partsresearch and sales departments that areknowledgeable, efficient and have beenwith the company for several years. Theuse of advanced telephone and computerequipment insures the quick handling ofyour order with personal service.

In our travels to the various industrymeetings, Tritronics' officers often havethe pleasure of meeting other people whowork their business with family members.The Tritronics family looks forward to serv-ing your business now and in the future.Our customers say that we are: LARGEENOUGH TO SERVE YOU, SMALLENOUGH TO KNOW YOU!

ZritronicsINCORPORATFDhas parts,accessoriesand serviceliterature forthe followingmanufacturers:

RCI1erles

Okii/raQuasar Technics Panasonic. MAGNAVOX

El SCOTT CC Tmerson. *Matsushita L FISHERSYLVANIA SHARP PH I LCo CASIO

PHILIPS/ft

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DENON PROSCAN SAGO

4.ICttronicsINCORPORATED


* * * DISTRIBUTORS' SHOWCASE * * *East Coast Transistor Parts, Inc.2 Marlborough RoadWest Hempstead, NY 11552Phone: 800-645-3516 Nationwide/CanadaPhone: 800-632-3323 New YorkFAX: 800-733-5904

East Coast Tansistor Parts, Inc. contin-ues as the preeminent electronics industryleader with the addition of Casio, PanasonicBatteries and Zenith. We have built upon areputation for speed, superior technicalsupport and an unsurpassed stocking abil-ity. With over 65 national parts distributor-ships, and over 200,000 parts under oneroof, we are poised to supply virtually anyelectronic component, no matter what theapplication.

We are a national parts distributor forAudio Technica, B&K Test Equipment,Beckman, Bussmann, Casio, Chemtronics,Dantona, Duracell, ECG, Eveready,Gemini, Hakko, Jabro, Kenwood, Mabuchi,Maxell, Nisshoku, Panasonic Batteries,Pickering, Pyle, Russell, Speco, Stanley,Tech Spray, Weller, Xcelite, Ungar, Vacoand Zenith.

East Coast is a full stocking distributor for

Zenith, Casio and Kenwood. We areKenwood's national authorized parts dis-tributor for Consumer Audio, AmateurRadio and Warranty Stations.

East Coast is a direct importer ofJapanese semiconductors. In fact, we'reone of the nation's largest sources ofsemi's, with prices that can't be beat. Weoffer large volume discounts and OEMquantities are also available.

Our sales/customer service staff are onhand to answer any questiols you mayhave concerning pricing or parts availabili-ty. Our highly trained technician's reputa-tion for providing technical assistance andanswers to our customers product ques-tions is unmatched in the industry. Our staffis available Monday thru Friday 9 -6 EST.For your convenience, our new state-of-the-art phone system allows you to placeyour order after our regular buE iness hours.

Our toll -free fax lines (800) 733-5904 arealso available to place your orders. TheEast Coast order lines are open 24 hours aday, 7 days a week. Customers receiveadditional discounts when they place theirorders via the fax lines or through our newautomated voice mail system.

Every order is given top priority at EastCoast. We deliver your purchase quicklyand with precision. Our quality control offi-cials oversee the warehouse/shippingdepartments to ensure you get what youpay for, the first time and every time youorder from East Coast. Overnight and sec-ond day deliveries are available for allorders placed by 3PM EST. While themajority of orders are shipped the sameday. you can be assured that all orders areready to ship within 24 hours from the timethey are placed. Customers may establisha Net 30 account or purchase by credit cardor COD.

While East Coast has grown over theyeas, we have strived to maintain the per-sonality of the small company we oncewere. Your business is important to us, andat East Coast we'll go the extra mile to proveit. Give us a try, you won't be disappointed.

For more information or for a free copyof our newest sales catalog featuring newprice reductions and incentives plus thevery latest products, call our toll free hot-line 3-Nationwide/Canada: 800-645-3516,New York: 800-632-3323.

EAS OASTSTANDS FOR THE BEST NAMES IN THE BUSINESS

CASIO KENWOODPICKERING

ECG WellefGEMINI. Beckman Industrial'

An ...we 0, Emerson EJecfr,C Co

Xcelite

Chemtronics NISSHOKU

JPRO. HIAMO O P ODPYLE Panasonic.

Batteries EIK

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CALL FOR A FREE CORYOF OUR NEWEST CATALOG

Nationwide: 800-645-3516New York: 800-632-3323

East Coast Transistor Parts, Inc. 2 Marlborough Road, West Hempstead, NY 11552 (516) 483-5742 Fax (800) 733-5904

Circle (6) on Reply Card 49


MAT Electronics975 Jaymor RoadSouthampton, PA 18966Phone: 800-628-1118FAX: 800-628-1005

MAT Electronics has expanded into a full -line parts distribution center, gearing itsinventory to the TV, VCR, computer monitor,and stereo repair industries. The growth ofMAT Electronics has been due to the follow-ing: quality products, competitive prices andfast reliable shipping. The company's prod-ucts are used by manufacturers, engineers,technicians, trade schools and hobbyists.

MAT Electronics stocks an extensive lineof flybacks (TV and monitor), Japa-nesesemiconductors, capacitors and MATVaccessories. In the past year, MATElectronics has started to distribute originalparts from Hitachi, NEC, Panasonic andSony at competitive pricing.

The company publishes an easy -to -read

80 -page catalog filled with thousands ofinventoried items, which can be accessedimmediately on their state-of-the-art com-puter system.

MAT Electronics is always current withmarket trends in the repair industry -alwaysemphasizing what is new in electronic partsand components -for VCRs, TVs, computermonitors and stereos. MAT Electronicssources its products from around the worldas well as domestically to give the best prod-uct at a true savings.

MAT Electronics takes great pride in itsability to accommodate the various needs ofall its valued customers. The company nor-mally ships orders within 24 -hours of receiptof your order, but UPS red and blue label

service is also available to ensure evenfaster delivery service if necessary.

The company takes pride that it has friend-ly and knowledgeable telephone operatorswaiting to take your phone call, and dealcourteously with any questions you mayhave about any electronic part. And, if youdon't see it in the catalog, just ask for it.

MAT Electronics takes the risk out ofordering from a catalog, offering a 90 -day,100% guarantee on all purchases.

Large volume discounts are available.Orders from foreign countries are no prob-lem. The company's toll -free lines are openweekdays 8:30 a.m. to 7 p.m., andSaturdays from 8:30 to 2:00 p.m., and a toll -free FAX number is available 24 hours a day.

VCR POPULAR POPULARFLYBACK

REPLACEMENT PARTS SEMICONDUCTORS REPLACEMENTS CAPACITORSVXP0521 Panasonic Idler $2.99ea (10 min)164113 RCR Idler Original $2.99eo (10 min)NPLY0111GEZZ Idler Original $7.95eo (10 min)613-022-2534 Sanyo/Fisher Gear S.69eo (10 min)199347 RCA Belt Kit 51.99coVTK-1 Video Tool Kit198522 Audio Bias OscillatorVSJS0018 Orig. Panasonic SolenoidVEMS0099 Panasonic Motor

$39.95ea$2.25eo$5.95eoS8.95ea

143-0-7504-01000 Fisher Belt157061 RCR Belt157062 RCA Belt

$.85eo (10 min)$.85ea (10 min)$.85ea (10 min)

MSU911 Toshiba RF Mod $14.95eoMSU951 Toshiba RF Mod $14.95eoVFI3409 Emerson RF Mod $14.95eoVR3422 Emerson RF Mod $14.95eoRTU006GEZZ Sharp AF Mod $14.95eoRTU0035GEZZ Sharp RF Mod $14.95eo

131J208R $1.99ea (10 min) 154-040R $19.95eo250869 $1.99eo (10 min) 154-074E 519.95ea25D1397 $1.99eo (10 min) 2434391 $24.95eo2501398 $1.99ea (10 min) 2434651 524.95ea25D1426 $1.99eo (10 min) 3214003 $24.50eo25D1427 $2.50eo (10 min) 043220011 $27.95eo2501650 $1.99eo (10 min) 79R307-1 524.95eo2501651 $2.50eo (10 min) 1-439-357-11 $26.95eo2501879 $2.50eo (10 min) F0014 $19.95eoJ00017 $11.95eo F0015 $19.95eoJ00069 $11.95eo F0016 $19.95eoSDR-3202-3 $6.50ea (10 min) F1588 $27.95eoSTK4273 $8.95eo (10 min) TLF14401F $29.95eaSTK0080 $13.00eo (10 min) TLF14423F $29.95eaSTK5481 $12.25eo (10 min) TLF14530 $26.95eoTR7777 $9.50eo (10 min) TLF14515F $26.95eo10114505A $8.95eo TLF14561F $26.95eoT0R8305 $9.50eo (10 min) TLF14801F $24.50eaUPD1705-C12 $9.95eo FCC141511L $19.95eo

FCM2015FIL $19.95eo

4.7M/160V Radio $.45eo (10 min)4.7NV250V Radio $.55eo (10 min)4.7N1/350V Radio $.65ea (10 min)1 ONV160V Radio 5.55ea (10 min)10M/250V Radio S.65eo (10 min)10M/350V Radio $.75eo (10 min)100M/50V Radio $.50eo (10 min)100M/63V Radio $.50eo (10 min)100M/100V Radio $1.00ea (10 min)100NV160V Radio $1.00eo (10 min)100M/200V Snop-in $1.00eo (10 min)100M/250V Radio $1.25eo (10 min)330M/200V Snap -in 10/for $19.90470M/200V Snap -in $1.99ea (5 min)680NV200V Snap -in $2.99eo (5 min)800M/200V Snap -in $2.50eo (5 min)153671 RCA Replacement $5.95eo270172-1 NAP Replacement $5.95eo

FREE 80 PAGECATALOG!

C.O.D Orders AcceptedWe Ship Throughout U.S. & Canada

MA ®ELECTRONICS975 JUROR ROAD SOITHAMPTON. PA 18966

viE Os TimErEcTRoNic DisTRibuoR,

CALL OUR TOLL -FREEORDERLINE

1.800.628-1118FAX# 215-364-8554


* * * DISTRIBUTORS' SHOWCASE * * *Diversified Parts2114 S.E. 9th Ave.Portland, OR 97214Phone: 800-338-6342 FAX: 800-962-0602

1994 is the year of Diversified Parts' 20thAnniversary as a distributor of OEM and GeneralReplacement Parts. The company specializes inthe sale of consumer electronic parts, acces-sories, chemicals and service literature.

As we look back over twenty years of tremen-dous growth we are especially grateful to our cus-tomers whose loyalty we treasure, and who havemade us one of the 'key players' in our industry.

But no celebration would be complete withoutsaying 'Thank You' also to the many fine manu-facturers and vendors Diversified Parts repre-sents; for it is they, who had the faith in our com-pany to get the job done for them.

So, after twenty years of continuous growthand service, we are where we are today, and whowe are today, because we had learned to listento what both our customers and manufacturersexpected from a successful distributor; and thatis to provide the very best 'Service, Service andagain Service.'

Yes, we are certain that it is indeed the levelof service we provide to both our customers andmanufacturers that sets Diversified Parts apartfrom many others in our industry. For we couldhave the greatest inventory and the highest per-centage fill -rate, but without the best possiblelevel of service we would be nowhere near themarket penetration and customer satisfaction wecurrently enjoy.

So, on the eve of our 20th Anniversary,Diversi-fied Parts invites all potential new cus-tomers to take advantage of the levels of servicewe provide. It might just be the best choice anddecision you've made in a very long time.

Diversified's Hours of Operation are Mondaythrough Friday from 8:00 AM to 4:30 PM WestCoast Time. You can call us on our toll -free 800 -Numbers for parts orders, research and account-ing. Yes, we are glad to even pay for your callwhen it is not an order, because your problems,inquiries and concerns become also our prob-lems, inquiries and concerns. Or if you prefer youcan reach us 24 hours a day, 365 days a year onour toll -free Fax Lines.

We extend to our customers the choice of anopen account, COD, or payment by VISA or MAS-TER CARD. And when you call us you have directaccess to our courteous and professional staff.At Diversified Parts you can still conduct businesswithout the use of automated telephone answer-ing systems or electronic voice mail. We are therefor our customers in person, whenever you call.

We ship by UPS and AIRBORNE EXPRESSfor a very low flat fee regardless of weight, zone,number of line items or different brands shipped.There is no shipping and handling fee for anybackorders generated off new orders. Yourorders arrive Red Label or the Next Day to 90%of all Zip code destinations, Blue Label or theSecond Day to the remaining 10% of locations.All orders are delivered nationwide in one to twodays! We call this level of service our DP TURN-

AROUND EXPRESS. Our warehouse staff worksevery evening until 8:00 PM. Our last scheduledparts pick-up of the day is at 7:00 PM West CoastTime, that is 10:00 PM East Coast Time.

Diversified Parts warranties all parts we sell,we do not have minimum orders, and we have inplace perhaps the most liberal return policy of any

distributor in the country. To all of these levels ofservice add quantity discounts and continuoussales and promotions, and you might just havefound in Diversified the kind of distributor that'talks your language.' We'd love to hear from you!Start *o rely on Diversified Parts for your bestchoice and diversity in parts, accessories andchemicals; but above all, rely on us to provide foryou the level of service you should expect from adistributor where you spend your money.

As we look to the future for Diversified Partsover the next twenty years to be part of our grow-ing electronics industry, nothing would make ushappier but to count you among our many fineand prosperous customers from Coast to Coast.

YOUR ORDER InBY 12:00 NoonWestcoast Time

FLAT 54.95 GROUNDvia UPS and USPS for ouropen accounts 'egardless ofweight. zone, number of lineitems. or dillerent brandsshipped to the I.:plowing ppcodes835 973.978838 980.986

988.994

No S611 lees for anybackorders generated of Inew orders.

TURN -AROUND

EXPRESS

NEWFOR YOU !

YOUR ORDER OulBy 5:00 PMSame Day

FLAT 55.95 2ND DAY AIRvia AIRBORNE EXPRESS

for our open accountsregardless of zone. number

of line items. or dillerentbrands shipped to all zip codes

other than those listedunder Ground encept Alaska.

Haw. and any packagewe ghing over tie pounds

No S&H lees for anybackorders generated off

new orders

"All orders delivered nationwide in one to two days"

IFLJTEK

Panasonic..0..y 0woci ar eu nm

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Products L__'TOSHIBAJ

KENWOODMENUMASTER'

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PhilipsECG

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Call (800) 338-6342 or FAX (800) 962-0602for

your best choice in parts, accessories and value-added servicesand experience

IN TURN -AROUND EXPRESS

E) DIVERSIFIED PARTS2114 S E 9ch Assam, Poctland Oregon 97214 1503) 236-6140

"WHERE THE COMPANY IS GENUINE AND THE PARTS ARE ORIGINAL.'

Circle (36) on Reply Card51


Andrews ElectronicsPO Box 914Santa Clarita, CA 91380Phone: 800-289-0300 805-257-7700 FAX: 800-289-0301

What is the most important quality thatyou as a servicer look for in a distributor?Is it an extraordinary supply of parts onhand or superior service? By itself, eitherwould be practically useless. Welcome to

Andrews Electronics, the best of bothworlds!

We are the most well -stocked wholesaledistributor of our kind, with over 250,000line items in our warehouse an average

WHEN IT COUNTS...

COUNT ON THE A TEAM!

ANDREWS ELECTRONICS & O.E.M. PARTS!!!

** A TEAM REQUIREMENTS ***

r> Over 1/4 MILLION line items in one location

C> Over a 907 FILL -RATE

C> Automatic Backorder & ETA reports

17> One of the most Efficient Research Departments

C> Factory Authorized for 15 major lines

r> HIGHEST Same -day processing rate

C> FREE or Discounted freight program

LQ No minimum orders / No handling charges

AIWADELCOEMERSON

THE STAR PLAYERS...GE* PANASONIC RCA*HITACHI PROSCAN* SHARPOPTONICA QUASAR SONY

TECHNICS TOSHIBA ZENITH

FOR DAY -IN, DAY -OUT PERFORMANCE...

COUNT ONBeandrewselectronics

P.O. Box 914. Simla C.:Ult.'. 91380-9014INQUIRIES: 805-257-7700 or FAX 805-295-5162

DIAL OUR 24 -HOUR ORDER DESK!PHONE: 800-289-0300 or FAX: 800-289-0301

* PREMIER DISTRIBUTOR

fill -rate of over 90%, and over an acre offloor space filled with parts, all in one loca-tion. We are the largest supplier in Americafor the majority of the manufacturers thatwe represent.

Just how dedicated is AndrewsElectronics to service? We were the firstdistributor to supply RCA/GE and Zenithparts to the service industry. Andrews wasthe first to pioneer a computerized systemfor inventory control/updating and orderprocessing, even before most of the man-ufacturers! Also, we were the first to offeran 800 line for ordering parts. Is it startingto sound like we wrote the book on OEMParts Distribution?

We've built our reputation on a very sim-ple philosophy ... service. Not very fancy,but pretty effective. Our constant growthattests to it. You see, all our policies thatdeveloped over the years have beenbased on that one simple thought: "Howmay we better serve the industry?" Howabout:

15 major brands to save you time, frus-tration, and money with "one -stop shop-ping"

Orders placed before 2:30 PST areroutinely shipped the same day

A freight program that offers free or dis-counted shipping

No minimum orders and no handlingcharges

Automatic backorder reports withETA's mailed biweekly

A fast, highly efficient research depart-ment. second to none

A program that converts make/model/descriptions to part numbersinstantaneously for the majority ofresearch requests

24 -hour toll -free phone and FAX orderlines

Over 80 full-time employees waiting toservice your needs.

And we don't just talk about better ser-vice and part availability . . . we formulat-ed it, believe in it, and stand behind it! Wellinto our fifth decade of serving the indus-try's OEM needs, Andrews is the old-timerin a relatively young field. Our seasonedstaff has combined old-fashioned princi-ples with innovative and fresh ideas utiliz-ing the latest state-of-the-art technology.

Wouldn't getting those extra unitsrepaired a week or two sooner be good foryour reputation? Sure, it would. And, wecan help. After all is said and done, it isperformance that counts. We know thatyour ability to perform your job dependson how well we perform ours.

Our regular office hours are from 8:15to 4:45 PST and we're closed for lunchbetween 12:00 and 12:30.

When you think of electronic parts . . .

think of Andrews.Circle (33) on Reply Card



MCM Electronics650 Congress Park Dr.Centerville, OH 45459-4072Phone: 513-434-0031FAX: 513-433-3272

Best brands in the businessMCM Electronics is a company dedi-

cated to developing the finest test equip-ment on the market. MCM offers namebrand test equipment like Fluke, Leader,B&K, and Hitachi because we are the rec-ognized leaders in the electronic serviceindustry.

A new name emergesOne name that is rapidly emerging as

the top choice among service techniciansis our own TENMA Test Equipment. EveryTENMA product is engineered to exact-ing industry standards required to meetthe needs of professionals in service,research and development, production,testing and training. Regardless of yourmeasurement or test application, TENMAdelivers reliable performance, accuracy,functional design and dependability.

Known throughout the industry as "TheWorld's Most Affordable Test Equipment,"TENMA offers unsurpassed value acrossa broad range of products. These prod-ucts include oscilloscopes, uriversal testcenter, monitor tester, spectrum analyz-er, digital analog multimeters, DMMs anda variety of special purpose test equip-ment for your service needs.

Discover for yourselfMCM publishes two full-sized catalogs

each year. Every issue introduces hun-dreds of new products with at least 30pages devoted to test equipment. Not onlydo we have an extensive line of test equip-ment, but we also stock over 20,000 of themost commonly used replacement partsand components in the electronics indus-try. Sales f"yers are also mailed regularlywhich feature specially priced products.

These flyers keep our customers con-stantly informed of new items that arebeing added.

Superior customer serviceMCM's sales staff is trained to answer

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Business Corner

mt:A7.1

Will Total QualityManagement work foryou? Part sevenBy John Ross

This is the seventh part in the BusinessCorner series on W Edwards Deming'sTotal Quality Management.

TQM Point 7Institute leadership. The aim of leader-

ship should be to help people, machines,and gadgets do a better job. Supervision ofmanagement is in need of an overhaul, aswell as supervision of production workers.

The responsibility for leadershipEveryone will readily agree that man-

agement has the responsibility for leader-ship. To achieve and maintain their lead-ership, managers should work to findwhat factors keep employees from doinga better job. In some cases, deadline pres-sures, attempts to please certain custom-ers, and internal competition make qual-ity more difficult to achieve. Much of thisexists because owners, top-level manag-ers, or supervisors have become separat-ed from day-to-day employee activities.

Since a management position may re-quire different skills than a purely tech -

Ross is a technical writer and microcomputer consultant forFt. Hays State University. Hays. KS.

nical position, managers may lose contactwith the technical side of the organiza-tion. Moreover, some managers may nothave any need or willingness to con-stantly upgrade their technical skills.

For example, a friend of mine, "Gene,"recently moved into a management posi-tion with a well-known computer net-work service company. As Gene's prior-ities shifted from troubleshooting to em-ployee relations and other managerialduties, he became less aware of the chal-lenges faced by the technicians under hissupervision. In addition, he became moreconcerned about pleasing his superior.

After a period of time, Gene found him-self placing the same demands on his em-ployees that had nearly driven him awayfrom the company. A short case historyillustrates how problems can occur.

Dealing with problemsWith the introduction of a new version

of a network operating system to a cus-tomer site, Gene's employees had diffi-culties with various software applica-tions, compatibility, and system memoryallocations. Because the technicians hadno prior experience with the new system,they were learning about the softwarewhile working at the customer site.

In one instance, the entire system"locked up" while the customer's admin-istrative assistants were working with alarge spreadsheet calculation. When thecustomer complaints arrived at Gene'sdesk, he realized that he had not provid-ed his employees with the new version ofthe software or any formal training con-cerning the local -area network.

Blaming his employees for the system


problems would have been the easy wayout of the predicament for Gene. Givenhis position, the customer would have ac-cepted that kind of explanation. However,he answered the customer complaints bypersonally visiting the customer site andtaking responsibility for the problems.

In addition, Gene scheduled an officemeeting with his employees, listened totheir complaints, and again accepted re-sponsibility for the problems. After thosemeetings, he drafted a company policythat covered the needs for formal trainingand resource development.

Taking responsibility andcorrective action

The situation that Gene encountered re-veals several positive results of his man-agement style. Since he assumed respon-sibility for the system problems, he actu-ally gained credibility. Both his custom-ers and his employees respected his hon-esty and leadership. Although the cus-tomer had complained about the diffi-culties, Gene's on -site appearance led toan even larger network system installation.

While his employees respected both histaking responsibility and his incisive ac-tion, they also respected Gene's priorities.By attempting to eliminate the barriersthat prevented them from performingwell, Gene demonstrated that the qualityof their work-rather than the quantity oftheir work-stands as his first priority.

Management/employee balanceThe situation encountered by Gene and

his solution for the problem also illus-trates the balance that must exist betweenmanagement and employees. WhileTQM originator W. Edwards Demingcalls for an overhaul of the supervision ofboth entities, real life may show that a bal-ance between the two forces may implic-itly provide both the changed supervisionand enhanced performance.

The lack of adequate performance bythe employees caused management to re-evaluate its priorities. In effect, the em-ployees instituted an overhaul of man-agerial supervision by showing why theycould not accomplish management'sgoals. Rather than become preoccupiedwith pleasing superiors, both the man-agement and the employees again lookedat the overall organizational goals.

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Audio Corner

Audio and commercial soundservicingRon C. Johnson

This month let's talk about some handygadgets that can help in servicing audioand commercial sound equipment. Someof them are for bench service but somecan also be used when you're field test-ing equipment at the customer's location.There are all kinds of useful (and expen-sive) pieces of test equipment availablethat you may already have on your bench:a multimeter, an oscilloscope, and usuallyan audio or function generator. But thereare a few more handy and less expensivegadgets that you can build yourself.

A portable signal sourceFor troubleshooting audio equipment,

Johnson is a journeyman electronics servicing technicianand an instructor of technology at the Northern AlbertaInstitute of Technology in Edmonton, Alberta, Canada.

as with any other electronic equipment,you have to narrow the problem down toa specific area before you can look for faul-ty components or connections. To do thatit helps to be able to inject a signal and thencheck its progress through the equipment.

For this you need a signal source. Youmay have a function generator on thebench, but you may not want to carry italong out in the field. Of course there areportable signal sources available that youcan buy, but it really isn't that difficult toput together a little battery -powered os-cillator that you can keep in your tool box.

Figure 1 shows the schematic of a sim-ple phase shift oscillator that will do thejob for you. This circuit is cheap (anddirty, to be sure), but it will give you anaudio signal at about 800Hz. Actuallyphase shift oscillators are notorious for

their temperature sensitivity so the fre-quency will change if you're working ina cool area. The potentiometer allows ad-justment of the output amplitude and thecircuit is powered from a 9V battery. Youcan build it into a small box and keep itin your tool box.

An alternate to this idea would be a 555timer circuit like the one shown in Figure2. The 555 is operating as an astable mul-tivibrator (a pretty familiar circuit, to saythe least). Of course this circuit providesa square wave, the advantage of which isthat you can get a better idea of any fre-quency response problems. It's relativelyeasy to see if the output waveform is dis-torted or high frequencies rolled off (if thecorners are rounded).

Another possibility would be the cir-cuit shown in Figure 3, a pink noise

.01uF L .01uF

R10k

R10k

Phase ShiftNetwork

.01uF

Feedback

R1

R2

Vcc12 volts

33k RC <4.7k

2N2222A

18k

Cout

Q1

10 ohm

- ground

C' B

2. kT4 .7 uF

Output

Figure 1. A Phase Shift oscillator.

-)E5 Electronic Servicing & Technology April 1994

Vcc

4

Reset

Trine!' Output

555 Timer

Discharge

5 CtrlVoltage Threshold

Ground

7

4k

3k

0.1 uF

Output0

Figure 2. A 555 timer astable.

2N2712

/Mg

.1 IT

1M

Vcc

2N2712

Ground

lilno

.1 1.1F

HoOutput

.n115 uF

Figure 3. A Pink Noise generator.

source. Pink noise consists of frequenciesshaped to give equal energy per octavethroughout the audio frequency range.Pink noise is handy for checking the fre-quency response and sound pressure lev-els of a sound system. Ideally, you wouldalso have a real time analyzer (frequencyresponse display) or at least an SPL meter

to check the sound pressure levels at var-ious spots in the room.

Microphones and speakersIt's also handy to have a couple of mi-

crophones for checking sound systems,both high and low impedance. If you havea real time analyzer you'll need a good

quality low -impedance microphone as aninput. Actually, to do the job right, itshould be a special calibrated microphonewith a very flat response (these are pret-ty expensive, but so is a real time analyzer).

As previously mentioned, an oscillo-scope is great to have on the bench, butmost of them are a bit bulky to carryaround on service calls and installations.You can use your meter to get a crude indi-cation of signals at various points in a sys-tem, but it doesn't tell you much. One pos-sible solution would be a portable oscillo-scope. These are now available from sev-eral manufacturers.

At the output end of audio equipmentyou need some kind of a speaker load. Onyour bench you can keep a small book-shelf speaker, and you could carry onewith you as well but they are bulky andeasy to damage. The other problem is thatyou need to be able to crank up the signaland really drive the load to check for dis-tortion, equal clipping, limiting (on someamps) and thermal problems.

For this you need a dummy load (two,actually, for stereo amps). You can buythese, too, but they're inexpensive andeasy to make using some high power re-sistcrs. For a few dollars you can get acouple of 200W, 80 resistors and mountthem on a board or in a ventilated box. Amuffin fan could be useful here to keepthem cool.

Special cables are useful for servicingThe simplest gadgets that can be use-

ful on the bench or in the field are a vari-ety of special cables. Usually, it isn't thelack of anything else that slows you down,it's the fact that you don't have the rightcable to connect a couple of pieces ofequipment. So, it's a good idea to makeyourself up a bunch of cables and adap-tors and keep them in their own kit.

Here's a list of some of those cables,connectors and adaptors:

low impedance microphone cable(XLR connectors),

high impedance microphone cable(some of the older mics have special con-nectors at the microphone),

a couple of heavy speaker cables (16gauge or heavier),

RCA to RCA cables (double cableslike those with a tape deck),


Figure 4. Cable for checking current

u.1. , , ,wale 7

44 74 U yt i 6 1166 1 l -II ? INt GO"

''', 1111 ' .111.4

-

,..,., $,..'.o. r ..'"i17,17,01.1

re I Till 91.eller

*dir

Figure 5. This portable audio test unit includes a public address amplifier. connectors, adapters,speakers, and other audio test equipment.

1/4 inch phone plug cable, 1/4 inch to RCA plug adaptor, 1/4 inch, RCA and XLR to alligator

clip adaptors, XLR male to male and female to

female adaptors, AC power cord with alligator clips (be

careful with this one), an assortment of XLR, 1/4 -inch, RCA

plugs and jacks, plus some lengths of var-ious kinds of audio cable.

One special ac power cable that is espe-cially useful in the shop for troubleshoot-

ing power amps is shown in Figure 4.Note that one side of the power is inter-rupted and can be connected through anac ammeter. When troubleshooting pow-er amps that have blown output transis-tors you can replace the parts you knoware faulty and then bring up the powerslowly using a variable transformer. Theammeter will allow you to see the currentstart to increase and you can shut the ampdown again before any damage is done.

A portable audio test unitOne obvious problem with this collec-

tion of cables, connectors and adaptors iskeeping it all together and in good shape(not to mention hauling it all over town).One partial solution I found was to builda portable audio test unit (Figure 5). Start-ing with an inexpensive, low power pub-lic address amplifier, I built a portablebox and mounted all the connectors,adaptors, speakers, dummy loads, high -to -low -impedance transformers, 70Vline transformers, and other parapherna-lia. A removable cover on the front pro-tected all the connectors and amplifiercontrols and a hinged door in the backallowed storage of cables.

I also brought all the connector wiringout to a long terminal strip on the frontpanel just in case I needed to connectwires directly to the unit. The box waspretty crude (made out of thin plywoodon a frame of one by twos) but overall theunit was quite useful (albeit a bit heavy).

I could plug in any kind of microphone,auxiliary (tape deck, etc.), or line input.(I even had a phono preamp with equal-ization for magnetic cartridges). A micro-phone impedance transformer (high sideconnected to a 1/4 -inch jack and low sideto an XLR connector) allowed micro-phone impedance conversion. An inter-nal 70V speaker transformer allowed anexternal amp to drive a speaker load orthe internal dummy load.

The internal amplifier also had its 42and 8S1 and 70V outputs brought out toI /4 -inch connectors so an external speak-er could be driven. In the top of the boxI mounted two 4 -inch ceiling speakers,one connected directly to a 1/4 -inch jack,the other with its own 70V transformer,also connected to a jack.

When it was done I could drag it alonganywhere I went and check pretty wellany kind of audio equipment. The ampli-fier didn't have a great frequency re-sponse or distortion figure (commercialsound amps generally don't) but, for aquick check it served its purpose. Lateron I acquired an SPL meter and a real timeanalyzer with built in pink noise genera-tor. Although it was a lot to carry, this col-lection worked out well for testing.

There was nothing high tech about thisunit but it did serve the purpose, saved mesome time in field and it also gave my em-ployee some exercise carrying it in andout of the job site.

58 Electronic Servicing & Technology Apr.I 1994

Computer Corner

Sources for monitor schematicsand partsBy John Bachman

Two problems in servicing computermonitors are where to get schematics, andwhere to get parts. Schematics and othertechnical data are nearly impossible toacquire for many monitors. Some manu-facturers are willing to sell their schemat-ics and technical manuals; many will not.Some manufacturers cannot be found.This article will help with the schematicproblem, but there are monitors for whichno data is available.

Finding parts is not as difficult as find-ing schematics, but it still can be a prob-lem. Some manufacturers try to controlparts availability but a third party moni-tor parts industry fills much of the gap.Most parts can be found if you knowwhere to look. But, once again, there aresome parts that are simply not available.This article will provide a list of partssources that should solve this problem.

Technical manuals and schematicsThere are two sources for schematics:

manufacturers and reverse engineeringcompanies. Some manufacturers will sella copy of their technical manuals and/orschematics which are generally very ac-curate, giving you all of the details, op -

Bachman is President of AnaTek Corporation

tional circuitry and design changes. Somemanufacturers restrict the information totheir authorized dealers and repair centersbut will supply parts.

The requirements for becoming autho-rized vary from just asking (Tatung) tobeing required to attend lengthy trainingsessions overseas (KFC), and everythingin between. If you want to become anauthorized service center call the manu-facturer and ask about their requirements.Table I lists the manufacturers and theirpolicies on schematics, technical manu-als and parts.

Reverse engineering providessome schematics

Reverse engineering companies pur-chase a monitor, disassemble it and tracethe circuits to create a schematic. The re-sult is usually representative of the unitthat was disassembled, but cannot reflectany design changes, updates or optionalcircuitry. Management Information Tech-nology (513-339-8095) has an extensivelist of reverse engineered schematics andis especially strong in the Packard Bellproduct line.

PartsParts availability is a happier story than

technical documentation due to an activethird party parts industry. While somemanufacturers will sell replacement parts(see Table 1) they are usually the mostexpensive source. If you can find an inde-pendent source for the part you need, andyou usually can, it is likely to be less ex-pensive than the manufacturer's part.Table 2 lists distributors who specializein unique monitor parts.

Other sourcesBecause computer monitor servicing

information and replacement parts havebeen so hard to obtain, companies havebeen formed that provide servicing tips,as well as information on finding sche-matics and replacement parts.

Manufacturer operated bulletin boardsystems are another source of technicaldata. To access a bulletin board, you needa computer equipped with a modem.Acer's bulletin board, 408-428-0140, in-cludes information on common failuresand engineering design changes. PackardBell's bulletin board, 818-773-7307, pro-vides basic technical data on all theirmonitors, but not much troubleshootinghelp. Other manufacturers restrict accessto their bulletin boards to authorized ser-vice centers.

Table 1-Manufacturers Manuals and Parts Policies

Manual PartsManufacturer Available Available "Idephone Comments

Aamazing No Yes 714-255-1688

Acer Yes Yes 800-733-2237 *Acer's bulletin board, 408-428-0140800-652-6672

Compaq No No 800-345-1518 Compaq suggests that you contact the800-652-6672 nearest Compaq authorized distributor for

parts. Call Compaq to identify a distributornear you.

CTX Yes Yes 800-342-5289


Manual PartsManufacturer .kNailable Available Telephone

Dell 'swill, Some 800-624-9896

Epson No No 800-922-8911

Goldstar Yes Yes 800-922-8911

Hitachi Yes Yes 800-225-1370X319

IBM No Yes 800-426-7282

KFC No Yes 800-253-2872(Kuo Fong Corp.)

Matsushita Yes Yes 800-447-4700201-348-9090

Nanao Some Yes 800-800-5202

NEC Yes Yes 800-388-8888

Packard Bell No Yes 800-398-3003

Relisys Yes Yes 408-456-6900

Sampo Yes Yes 404-449-6220

Samsung Yes Yes 800-446-0262800-627-4368

Sony Yes Yes 800-352-7669800-488-7669

Tatung Yes Yes 800-827-2850

Xtron Some Yes 201-798-5000

Zenith No No 800-553-0331

Comments

Dell does not support their monitorsdirectly, but will refer inquiries to themonitor manufacturer.

Epson monitors are difficult to supportbecause of unavailabilityof technical dataand parts.

IBM supplies only subassemblies,no component parts.

KFC supplies service manuals only toauthorized dealers.

Service manuals are available only forolder models of Nanao products.

NEC makes manualsand parts availablefor older models only,(up through "D"models are currently available).

Packard Bell service manuals are availableonly to authorized service centers. PackardBell's bulletin board, 818-773-7307.

Relisys schematics and Q -Squared parts areavailable through Q -Squared, 2035 O'TooleAvenue, San Jose, CA 95131.

Service manuals are also available throughdistributors such as J&J International andArocom(See "Parts"section of this article).

Sony will refer you to a distributorwho can supply you with what you need.

Xtron has been out of the monitor businessfor several years, but they still supply sometechnical manuals and parts.

Zenith treats monitors as non -repairable.Therefore, the only parts they offer arecomplete monitors. There are over 700authorized service centers.


Distributor

AmcoTron14821 Spring AvenueSanta Fe Springs, CA 90670800-344-3882Fax: 310-802-0061

Table 2-Monitor Parts Distributors

Flyback Monitor MonitorTransformer IC's Semicond

Yes

Schematics

Yes Yes Samsung &Samtron

B & D Enterprises No Yes Yes No452 Hamburg TurnpikeWayne, NJ 07470800-458-6053 or 201-628-7373Fax: 201-696-5623

Consolidated Electronics705 Watervliet AvenueDayton, OH 45420-2599800-543-3568 or 513-252-5662Fax: 513-252-4066BBS: 513-252-9992

Yes Yes Yes Yes*Howard W.Sams & Co.

Computer Component Source Yes Yes Yes No135 Eileen WayPO Box 9022Syosset, NY 11791-9022800-356-1227 or 516-496-8727Fax: 800-926-2062

CRC Components, Inc. Yes Yes Yes Yes186 University ParkwayPomona, CA 91768800-822-1272 or 714-468-9711Fax: 714-468-9667

Dalbani Corporation Yes Yes Yes No4225 N. W. 72nd AvenueMiami, FL 33166800-325-2264Fax: 305-594-6588

Digi-Key Corporation No Yes Yes No701 Brooks Avenue SouthPO Box 677Thief River Falls, MN 56701-0677800-344-4539Fax: 218-681-3380

FOX International Limited Yes Yes Yes No23600 Aurora RoadBedford Heights, OH 44146800-321-6993Fax: 800-445-7991

J & J InternationalPO Box 5778Parsippany, NJ 07054800-627-4368Fax: 201-884-4378

Yes Yes Yes YesSamsung &Samtron

LEAD Electronics, Inc. Yes Yes Yes No8370 Thompson RoadCicero, NY 13039315-699-6099Fax: 315-699-6280


Distributor

MAT Electronics975 Jaymor RoadSouthampton, PA 18966800-628-1118Fax: 215-364-8554

MCM Electronics650 Congress Park DriveCenterville, OH 45459-4072800-543-4330Fax: 513-434-6959

Mouser Electronics2401 Highway 287 NorthMansfield, TX 76063-4827800-346-6873Fax: Various

Prelco ElectronicsDistributors605 Chestnut StreetUnion, NJ 07083-9318908-851-8600Fax: 908-686-4656

Russell Industries, Inc.3000 Lawson BoulevardOceanside, NY 11572800-645-2202 or 516-536-5000Fax: 800-645-2200 or 516-764-5747

FlybackTransformer

Yes

Yes

No

No

Yes

MonitorIC's

Yes

MonitorSemicond

Yes

Yes Yes

Yes Yes

Yes Yes

No No

Schematics

No

No

No

No

No

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Portable ionizerThe Portable Ionizer from Richmond

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1111111111111111

NTI rarer

VOPEX 8M

Splitter for monitor burn -inNetwork Technologies Inc., introduces

the VOPEX-8M video splitter which al-lows one MacIntosh to drive eight moni-tors, all displaying the same image simul-taneously. With 10MHz bandwidth, thisdevice displays images as crisp as theoriginal. All of the monitors connected tothe unit must be the same type and can beplugged directly into any of the eight out-put ports. The splitter can be used by de-pot repair centers, as well as monitor man-

ufacturers by allowing eight monitors tohe burned -in from one Mac computer.

The unit is compatible with All Mac'sthat have external monitors. It connectsdirectly to be video output port via athree-foot supplied interface caple.


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ITT Pomona has introduced three newhigh -voltage probes to provide improvedmeasurement versatility when used withDMMs and oscilloscopes.

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CORPORATION ErKPO Box 1200/ 100 Memmack Road / Amherst. NH 03031


to run on any IBM compatible computer.What RepairMan does is automates in-

voices and keeps records for repair busi-nesses. It records the exact date and timeof steps in the repair process with twokey -strokes. The computer automaticallydetermines the status of the repair for easyretrieval by category. A list of all unitsthat are waiting on parts is kept, as wellas those units waiting for estimates, or tobe picked up. It also prints invoices, claimtickets, and unit tags on plain paper.

For the months of April and May, thecompany is offering the program at a spe-cial introductory price. In addition, a tech-nical support line will be provided. Amanual is included for reference.


Software tools

CyberMedia Inc. announces three soft-ware tools for MS/PC-DOS, Windowsand NetWare users, network administra-tors, technical -support engineers andsoftware developers.

PC911, which compiles system -levelinformation about the configuration of apersonal computer, checks this informa-tion each time the system is booted up for

March 1994 Electronic Servicing & Technology 63

Productshardware and software conflicts and otherproblems, then guides the user or techni-cal -support engineer in how to fix the sys-tem when a problem is encountered.

WIN WIN "unsticks" Windows bychecking the integrity of and tuning theWindows environment and leading Win-dows applications. When a user encoun-ters a Windows error message, Win Winpops up to detail how to fix the problem-with network administrators able to fixthe problem remotely.

MultiTalk for Windows automaticallytranslates the menus, dialog boxes andmessage boxes of any Windows programinto any one of 15 languages, in seconds.


Directory of electronic componentsThe Component Exchange, a directory

with listings of over 150,000 active andpassive line items offered from invento-ry by electronic component distributors,is now available.

In past years this directory was usedexclusively by electronic distributors as amedium within the trade for buying and

selling inventories. The 1994 issue hasbeen broadened to meet the needs of theentire industry. Sources for hard -to -findcomponents and inventory used for smallproduction runs are listed by manufac-turer, part number and source. Once a partnumber is located, a code number leadsthe user to the distributor with inventory.Included is a contact phone number.


O

tHighlight

this opportunityto enrich your skills

at the 1994 National ProfessionalElectronics Convention, August 8-13,

in Portland, Oregon. Programs will include Hands-on Technical Training Certification

Management Seminars industry Trade Show. Register and pay by April 30 to

$AVE UP TO $100 PER PERSON.For a registration form or more information,

rush the following to NESDA:Name

Business

Address

City State

Zip

Phone

NtionI Electronics Service

NESDADealers Association. Inc.

2708 W. Berry St.Ft. Worth TX 76109

(817) 921-9061

News (from page 5)

keting and advertising, strategic plan-ning, family business and legal issues,and other subjects.

Tuition scholarships will be part of theexpanded value of the new School ofService Management. The registrationcost is expected to be $299.00 and the ser-vice divisions of a number of manufac-turers will be offering scholarships totheir authorized service agencies andself -servicing retail dealers.

"We recognize that success in the 90swill depend on creating alliances with or-ganizations that have similar missions,"according to NARDA president, ConMaloney, Cowboy Maloney's, Jackson,MS. "The increasingly complex demandsof doing business as we enter another cen-tury require us to leverage each other'sstrengths with these alliances."

NARDA formed such an alliance withthe Association of Home Appliance Man-ufacturers (AHAM) last year to create theEPA approved Technician CertificationTest for CFC Recovery. This alliance be-tween NASD and NESDA is another stepin that process.

hiprove Your Form.343a..4. A coninuous feed forrn

" used fcr customerc.o.d. service or parts/accessory salesreceipts (N3CS-X). Not for warrantybilling.

5 -Part

7 -Part

A continuous feed formfor warranty billing.

A universal snapoutform (N7SN) designed

for both customer service c.o.d. andmanufacturer warranty billing.Complies fully with the requirementsof state and local ordinances.including California.

Discounts CaNESIV FormsIAess

are available to NESDA members atadditional savings. For pricinginformation and samples, orinformation regarding other NESDAmembership benefits, contact the NESDA office.

p.m.. amain. 0a

SZ=.7 EZ:

glagsktiawm-4.se-Samms=7:_;;;-

WO. a...ammo

oak

The NESDA Form2708 West Berry St.

Fort Worth, TX 76109(811) 921-9061; Fax (817) 921-3741

64 Electronic Servicing & Technology March 1994

ClassifiedClassified advertising is available by the word or per column inch.By -the word. $1.65 per word, per insertion, pre -paid Minimum charge is $35 per insertion. Initials and abbreviations count as full words. Indicate freecategory head-ing (For Sale, Business Opportunities, Miscellaneous, Wanted). Blind ads (replies sent to ES&T for forwarding) are $40 additional. No agency discounts are allowedfor classified advertising by the word. Contact Linda Romanello at 516-681-2922 to place your classified ad (by -the -word). Mastercard, VISA, American Express andDiscover are accepted for FAX or mail orders.Per column Inch (classified Display): $235 per column inch, per insertion, with frequency discounts available, 1" minimum, billed at 1/4" increments after that 10"maximum per ad. Blind ads are $40 addition. Reader Service Number $25 additional to cover processing and handling costs. (Free to 4 -inch or larger ads.) For moreinformation regarding classified display advertising please call 516-681-2922. Optional color (determined by magazine) $150 additional per insertion.

Send your order, materials and payments to:Electronic Servicing & Technology, 76 North Broadway, Hicksville. New Ycrk 11801

Attn: Linda RomanelloPhone: 516-681-2922 FAX: 516-681-2926

FOR SALE

HELLO! Doctors Do It! Airlines Do It! Lawyers Do It!TVNCR TECHNICIANS SHOULD DO IT!In any profession, knowledge coupled withthe ability to quickly access case or servicehistory PAYS BIG!! A doctor's ability to diagnosequickly and confidently is largely attributed to useof and access to data and information of previous-ly diagnosed symptoms. Lawyers can predict theoutcome of their present case by using prior casehistories exhibiting similar symptoms. A productiveTVNCR technician will not rely on memory aloneto diagnose symptoms and part numbers. Insteadthey will call upon past case histories, which willenable the smart servicer to avoid the costly mis-takes of mis-diagnosed part orders and loss ofextremely valuable time ... From the original WorldWide TECH -TIP Program comes 2.5 Million Dollarsworth of actual solid repairs. 1987 through August1993. Whether you are computerized or not, ourTech -Tip program provides the most current com-prehensive published paper format that there istoday. You may also wish to choose our Tech -Tipcomputer program, licensed World Wide under(PARADOX) by The Boreland International Co.We're not fooling around and you shouldn't either.Remember it's not the quantity of tips but the con-stant update quality of part numbers and solutionsthat makes the difference. Our initial 10,000 TECH -TIPS cover VCR-VCP-TV/ VCR combo CD LD-FAX-Camcorder-VHS/ SVH/ C/8MM-Stereo-Moni-tors-Amps Projection Front and Rear -Microwave -Satellite. Category is easily cross-referencedfirst by Model, Chassis or FCC ID Number and print-ed out or simply scanned by Make and Category.Unlike other programs, we provide OEM Part num-bers and substitutes. Our on -going program is actu-al day-to-day repairs written on the Bench by tech-nicians for technicians. No need for you to spendtime updating your data base or paper binders. Wesend you a complete revised program at eachupdate of your choice (Computer or Paper Format).Outside technicians and students love the porta-bility and say it is a must in the field where time isvery critical. As an added Extra, we provide an FCCID Cross -Reference list which saves the expenseof purchasing Service Manuals you may alreadyhave and just don't know it. This program was pro-duced by Ed Erickson technician and owner of TV -Man Sales & Service, Inc., and President of TheProfessional Electronics Association of SouthFlorida. The PHONE CALL is "FREE" and so is theDisk or Paper Sample Demonstration. CALL (800)474-3588 or Write TV -Man (TECH -TIPS), 7040 W.PALMETTO PK. RD. #2-112, Boca Raton, FL.33433.

EXTENSIVE DATABASE, Electronic Part Distri-butors, Listed by Manufacturer. IBM/Compatible-$34.95 plus 4.50 S&H, Mastercard/ Visa 1-800-580-4562. Ext 80. TECH RESOURCE, P.O. Box1414, Noblesville, IN 46060. Brochure available.

FOR SALE

» TIPS SUPER SALE «THE TIP COMPUTER PROGRAM is now on salefor a special price. Over 13,000 TIPS & grow-ing !!! One of the LARGEST tip databases in theWORLD - TV's, VCR's, CAMCORDER's plusother electronic equipment. HIGH QUALITY PRO-FESSIONAL SOLUTIONS with up to 8 LINES ofproblem solving information. ADD your own tipsto the program and find them FAST !!! Stop writ-ing YOUR valuable repair tips on schematics.PRINT any tip. Special DATA EXCHANGE &UPDATE feature INCLUDED with every program.Our customers say this is the BEST technicaltip database program on the market today. Paysfor itself with 1 or 2 repairs. Works on ANY IBMcompatible computer with a hard drive INCLUD-ING 486. 386. AND older 286 & XT models.Updates & Network versions available. Used byNational, State & Local Electronic AssociationMembers & Officers. Only $175.00 I!! (High den-sity disks - specify size). Prepaid orders(check/money order) within the U.S.A. are shippedFREE. Call for: C.O.D., Double density disks, andshipping outside U.S.A. Have your own tips? Askabout our TIP EXCHANGE policy with FREEUpdates. Already have a tip program? Ask aboutour competitive upgrade Discount. P.S.-can'tfind the right software for your business or otherinterests? We write CUSTOM SOFTWARE to fityour needs. CALL NOW !!! (516) 643-7740HIGHER INTELLIGENCE SOFTWARE, 60Farmington Lane, Melville, NY 11747

DON'T BE MISLED BY OTHERTECHNICAL 71P PROGRAMS - SERVICE TIPSIS DIFFERENT FROM ALL OTHERS IT ORGANIZES 15,700 CURRENT SERVICETIPS IN ALPHABETICAL ORDER BYModel/Brand & Symptom with ConciseSolutions, Part Numbers, Values & Locationson ALL CONSUMER ELECTRONIC EQUIP-MENT. Created by 2 CET'S with over 20 YEARSexperience and a computer programmer. IT'S ANINDISPENSABLE TOOL FOR ANY SERVICECENTER. Members of electronics associationssuch as NESDA-NYS, NESDA, METSDA, TESA-LI use this program and confirm there is no bet-ter program available today. DUE TO THE OVER-WHELMING RESPONSE TO OUR PREVIOUSADS, * * * NOW for a LIMITED TIME ONLY SER-VICE TIPS is available for the low price of$129.95 Demo Disk & Quarterly Updates arealso Available - Call or Write Electronic SoftwareDevelopers, Inc. 826 So. Main Street, SouthFarmingdale NY 11735 Phone (516) 221-6403.

TEST EQUIPMENT BOUGHT & SOLD: OSCIL-LOSCOPES, ETC. 1-408-738-4206. FAX 1-408-736-6946.

FOR SALE

Tek 4656 100MHz scope $575, Tek 2215 60MHzscope w/TV Trigger $489, Many other scopesavailable. All in Excellent Condition. Call for listingof our used equipment. We buy surplus equip-ment. Test Equipment Sales (603) 434-2544.

VHS -VCR Repair Solution Sets I - IX. Each con-tains 150 symptoms and cures, cross referencechart, free assistance, $19.95 each, all nine$49.95. Visa/MC. Eagle Electronics, 52053 LocksLane, Granger, IN 46530.

Earn $$$ Repairing Zenith TV's to componentlevel -now over 1000 models 1983-1993.Guaranteed effective and reliable cost cuttingsymptom/cure format. Buy manual and receiveFREE eport, "Repair Shorted CRTs Fast" (rasterone color) $89.95. Demo Sampler $19.95. ZMEX.807 Queen Palm Lane, Sarasota, FL 34243.

MAKE MORE MONEY! In Your ElectronicRepair Business! New Report "COD Repairs -TV Servicers CASH Crank!" Reveals How! Send$39.0C + $2.00 S&H Check or M.O., of S.A.S.E.For More Info to: Electronic Services, P.O. Box461, Belleville, MI 48111. Guaranteed! Since1951.

TECHNICIANS, FINALLY A BREAKTHROUGHIN SMD REMOVAL! CHIP QUIKTM SMDREMOVAL KIT. NO DAMAGE TO CHIP ORBOARD "LOW OPERATING TEMPERATUREEASY TO USE INEXPENSIVE. $12.00 per kit +$2.00 S&H. 24 hr. Fax for credit card orders (508)879-7727 Info available, call MTS ELECTRON-ICS (508) 879-3131.

REDUCED 85%. Diehl Mark III $69, Diehl Mark VHorizontal circuit tester $179. New. Conductivecoating for remote control keypads $9.99 ppd.WEEC, 2411 Nob Hill Road, Madison, WI 53713.608-238-4629, 608-233-9741.

ZENITH MODULE REPAIRSSave Money Repair Your Own ZENITH Modules248 CURES 9-124 THRU A-9740 LASER PRINT-OUT $29.95 INCLUDES S/H MAIL CHECK TO:Electronic Software Developers Inc. 826 S.Main Street, South Farmingdale. NY 11735

TV CASE HISTORIES: Booklet with 1,750+histories. Satisfaction assured. Only $35 (two-daypriority shipping, add $1.90). Mike's RepairService, P.O. Box 217, Aberdeen Proving Ground,MD 21005. Same mailing address 30 years. SendSASE for samples. 410-272-4984, 11am-9pm.


FOR SALE FOR SALE WANTED

Sencore VA62A with VC63 VCR Tester and NT64NTSC Pattern Generator all cables and manuals,used VERY LITTLE - $2500.00. CALL 509-483-9440, 9:00 a.m. to 5:00 p.m. WST

SENCORE EQUIPMENT. EXCELLENT CONDI-TION. VA62, $1500.00; SC61, $1500.00; SG165,$500.00; CR31A CRT checker with universaladapter, $400.00; Cricket (ac), $150.00; CB41,$100.00, or all for $3500.00. 1-914-687-4309.

Sencore VA62 Video Analyzer, $1500.00;Sencore CR70, $500.00. Call 904-489-2036 or904-489-5105

VA62A with test fixtures, buy outright or makepayments. CALL Pete, 402-466-1900 days, 402-420-2333 evenings.

Sencore-CM2000, VA62, VC63, SCR250, LC76,CR70, 300 mixed Sams Photofacts 599 to 2700.$4500.00 plus S&H. Ken 716-795-9394.

SERVICE: M.I. TVNCR Repair servicing allmakes/models TVNCR's. Full line of qualityreplacement parts. Phone: 1-800-600-7033 or205-251-7033. Addr.: 2400 24th Street N., B'ham,AL 35234.

BUSINESS OPPORTUNITIES

MOVE TO THE LARGEST REPAIR PROFITMARKET IN THE COUNTRY - SUNNY SOUTHFLORIDA Think about it, our clients bring theirREPAIRS & MONEY from all parts of the world.Annual Gross 375,000k, take home 80 - 95,000k.Owner retiring, Fully staffed & operated in thelargest growth area of Ft. Lauderdale. Established12 years. No competition. Authorized 15 majorbrands. Totally computerized. Simple to operateBusiness. Price is 150,000k, Owner financingavailable. (305) 474-2677.

Experienced technician to service TVNCR's -Salary $10.00 - 15.00/hr. Phone: 1-800-600-7033or 205-251-7033.

MISCELLANEOUS

A.T.S. SPECIALTY PRODUCTS Drive belt/rollerregripping agents. and INSTA-PLASTIK GEARAND PLASTIC REPAIR KITS. Proven in over 3000service centers, INSTA-PLASTIK field repairsbroken parts, nylon gears and teeth. 15% OFFFIRST ORDER 1-800-343-3530.

CALL 516-681-2922OR FAX 516-681-2926TO PLACE YOUR AD.

Readers' ExchangeReaders' Exchange has been reinstated as a free

service.The following restrictions apply to Readers'

Exchange: Only individual readers may use Readers'

Exchange, and items must be restricted to thosethat are ordinarily associated with consumer elec-tronics as a business or hobby. If you're in busi-ness to sell the item(s) you want to offer for sale,the appropriate place for your message is in a paidadvertisement, not Readers' Exchange.

Readers' Exchange items must be restrictedto no more than three items each for wanted andfor sale. and may be no more than approximatelyfour magazine column lines in length (about 20words).

All submissions must be typed or printedclearly!

Send your Readers' Exchange submissions to:

Readers' ExchangeElectronic Servicing &

Technology76 N. Broadway

Hicksville, NY 11801

WANTED

One AD737 rms-to-dc converter; one Op- I 77GPPrecision Operational Amplifier. (908) 888-0608.

FME reel-to-reel tape recorder (manufactured byFederal Manufacturing & Engineering Corp.,Model 47-A or other); working or not, as whole unit,parts source, or parts. Also seeking literature onproduct. Contact Kevin Wheeler, 3907 SunbeamAve., Chattanooga, TN 37411, (615) 698-3643.

Good used yoke for Hitachi TV Models cri 9Z3,CT 1933 part number 2441558. Send price to DonAnde, 1666 S. Fares .1 ye.. Evansville, IN 47714.

Published inmate author/inventor seeks collabora-tor for ground -breaking invention. Experience withmicro -electronics a MUST! References available;send qualifications/phone. Contact Dale C.

Shackelford, FCC 1D#153259, 1012 W. Columbia,Farmington. MO 63640-2902.

Service Manual for Magnavox. Model T815-02AA.Need schematic that shows where diode DI on CRTboard #703917-3 is connected. (Photo of this onpage 42, Fig. 5 of June 1993 ES&T). Charles Hess,201 S. Oak St., Buchanan. MI 49107.

New or good used IC1410. synthesizer IC part #I5-3015689-1 for Sylvania Model CX0178WR.Chassis E53-02. Price TV, P.O. Box 291. ParkerCity, IN 47368, (317) 468-6858.

High -voltage focus block for #CT5061 Hitachi bigscreen TV, Part #161366; also need big screen mod-ule, Part #DUNTK 4039DE00, power supply forSharp PWB-C; new or working used parts. ContactAndrew or Shaun Scarborough, (912) 272-6561collect, day or night, or send post card toScarborough TV, 1418 Highway 199 South, OldRiver Road, East Dublin, Georgia 31021.

Motor Capstan #150538 for RCA VGPI70 VCR,Audio Video PCB 4-2284-041000 for FisherFVH922 VCR. L McHenry, 6225 N. 20th Lane,Phoenix. AZ 85015, (602) 249-2325.

Tips and heaters for Permax line of soldering irons(25w and 30w) or a source of supply for same; alsoManual set for Tandy Model 16B Xenix 15mb HDsystem; also Telephone line simulator, TeletoneTLS -3 or 4, B&K Elec. Design Teletester H or III.Please quote condition, availability and price. LMSElectronics, 11241 Northwest Seventh Street, CoralSprings, FL 33071.

Schematics for Coronado radio, Model #740 (BRC-740). Ed, (206) 631-9235.

B&K sockets for Model 470; B&K picture tubetester, numbers 27 and up. Chuck McDonald, 595Huntmere Drive. Bay Village, OH 44140, (2/6)871-6523.

New or used red CRT/Lens assembly. Part#705187-002 for Magnavox rear projection TV,Model #RF8505AK05. Kevin, (716) 265-41/3.

Manual/schematic for Stoddart NM2OB F/S meter,a.k.a. AN/PRM-I. Buy or copy & return. D.J.Robinson, 1277 Gatewood Dr. NE. Lawrenceville,GA 30243, (404) 962-3949.

New or good used 4ADC4 CRT, Sylvania IC, 15-3017815- I or ECG 865, interface IC in tuner of E5 I -44. Contact A -OK TV, 42 Creeping Hemlock Dr..Norwalk, CT 06851, (203) 847-9254.

FOR SALE

Sams Photofacts. 3 through 960. Some missing total395. $1.00 each plus shipping or make offer for all.Call Sigmund 7/7-264-3846.

About 40 to 50 year old parts, etc. Military surplustransformers, chokes, swinging chokes, and radiopower transformers and 6V and I2V vibrators-$2.00 to $3.00 each plus shipping. Send SASE foryour needs or more details. S. 0. Sellers. 7308Franklin Dr., Bessemer, AL 35023-5557.

We have for sale a Tektronix Spectrum Analyzer,model 492, serial B054732, in excellent conditionfor $9,000.00. Sherry Burks, Able VideoElectronics, 615-256-2852.

Sencore SC3080, VC93, PR57, and all 4 TentelVCR mechanical gauges. All with light use. CallRick, 315-699-3935.

66 Electronic Servicing & Technology March 1994

Sencore LC75 Z meter and SCR250 accessory,$500.00. Sencore VA62, used less than 100hrs.,$1500.00, B&K 3010 function generator, $95.00,B&K TRII0 isolation transformer, 4 outlets, 2direct, 2 isolated. $95.00., Leader LD2 1 dummyload, $50.00, Fluke 77 DM M and 80K0 high volt-age probe. $95.00. Orland Lynd, ORCOElectronics. 2300 Harvard Way, #124F, Reno, NV89502-4044.

2 Bell & Howell Microfiche viewers, $75.00 w/oprinter $175 w/printer. Excellent condition. Dave817-465-0257.

Sencore SC3080 80MHz waveform analyzer,$2.300.00/VC93 all format VCR analyzer,$2,000.00, Sencore PR57 variable isolation trans-former, $350.00. All new 12/92. lightly used thru6/93. All excellent cond., w/original boxes, manu-als, leads. etc. Will sell all for $4,000.00; will con-sider best offer. Must sell. Call Don at 1-313-498-3922. Leave message if no answer.

Brand new Sencore VC -93 VCR Analyzer. Contact1 (216)898-3339.

Sams Photofacts 1000-2336 for $1200.00; Audiomanufacturer's service data. 1960-1980, forPioneer, Sansui, Kenwood, Onkyo, Fisher. Scott,etc. Send large SASE for a list. Contact A -OK TV,42 Creeping Hemlock Dr.. Norwalk. CT 06851,(203) 847-9254.

A mtek AC surge and filter suppresser#MP208ERF.120/208 wye operating voltage,$3500.00; Metcal soldering iron power supply,$100.00; Signal Corp. Frequency Meter #BC -22I -AH, 25 Hz -20 MHz, $75.00: Kar Kar #KPN5725,8-16 MHz band suppression filter. 75/75 SI unbal.,$50.00; 10-9" Ball Electronics monochrome mon-itors $20.00 each. Contact (214) 524-0104

RCA Service Data Consumer Electronics Products,1967-1978, and Sams Photo Facts. Contact AnnBichanich, 15 1/2 W. Lake St., Chisholm. MN55719, 1 (218)254-4421.

LBO -52A Leader 35 MHz dual -trace scope: NLSMS -230 30 MHz dual -trace scope; Sencore SM152

marker/sweep generator; Tektronix Model 211portable scope. For sale or trade for Sencore VA62-62A. Contact 1 (914)679-6629 after 6 pm.

Tektronix 2244A 4 -Ch. oscilloscope. 100 MHz dig-ital readout w/pouch & cover, tilt swivel base. 4probes. includ;ng high voltage & service manual:like new, recent factory calibration, $2000.00 orbest offer. Also. Tektronix CMC250 2 -Ch., 8 -digit1.3 GHz multifunction frequency counter. Newcondition, in original box w/manual. $400.00 orbest offer. Contact Bruce (516) 437-2277.

Fluke 8024B handheld digital meter. $125.00:Amprobe RS -1 current clamp. $25.00: both itemsin like -new condition. Contact Ted, 15669 Couzens.Eastpointe. All 4802/. (810)777-5661.

Forty to 50 year old radios and intercoms (8 sta-tions/masters. etc.) and radio chassis complete withtubes (except speakers) and 1 or 2 electromagneticspeakers. $3.00 to $5.00 each plus shipping. SendSASE for your needs or more details. Contact S. 0.Sellers, 7308 Franklin Dr., Bessemer, AL 35023-5557.

Sencore CM2000 computer monitor analyzer withadapters, cables. and manuals in original box. Cost$3295.00, will sell for $3000.00. Contact Warren,(701) 845-3484. 9-5.30 CST.

Sencore ST66 stereo TV gen. $300.00: Fluke 37.$125.00: Tektronix 2213, 60 MHz scope, $600.00.Contact Bud, t413) 533-7566 after 5 pm EST.

ORGANIZE AND PROTECTYOUR COPIES OF

ES&TNow there's an easy way to organized and keep copies of your favorite magazine

readily available for future reference.These custom-made titled cases and binders are iceal to protect your valuable

copies from damage.They're designed to hold a year's issues (may vary with issue sizes), constructed

with reinforced board and covered with durable leather like material in red, title ishot -stamped in gold, cases are V -notched for easy access, binders have specialspring mechanism to hold individual rods which easily snap in.

Each binder is $9.95 plus $1 S & H ($2.50 outside the US).

Mail all correspondence to:

Electronic Servicing & TechnologyJesse Jones Industries. Dept. EST

499 East Erie Avenue, Philadelph a, PA 19134CHARGE ORDERS: (Minimum $15): AMEX. VISA. MC, DC accepted. Send card name, #, Exp. date.

Call TOLL FREE 7 days, 24 hours1-800-825-6690

Test YourElectronicsKnowledgeAnswers to the quiz(Continued from page 23)

I.No.lt is already a Wheatstone bridge.

2. The Q of a tuned circuit is calculatedby the equation:

Q = resonant frequency/bandwidthSo, Q = 500/15 = 33.3 (no units)

3. There are 271 radians in one revolu-tion. So, if

2a radians = 1 revolution200E radians = 100 revolutions

You may have learned to solve prob-lems like this by making a ratio -

2R: 1 rev. = 200/1: x rev. (therefore x =100 rev.)

4. No. If you try it you will destroy bothelectrolytic capacitors!

5. Clockwise. The small wheels arecalled idlers. They do not reverse thedirection of the large wheels.

6. Anthropomorphous or Anthropo-morphic. (not cyborg!)

Both answers are correct. If youranswer was correct give yourself twoextra bonus points for knowing the wordand another two points if you spelledyour answer correctly.

7. It is called the measurand. Take offfour bonus points if you called it "thething being measured."

8. The Thompson Effect. It is one ofseveral important thermoelectric effects.

g. It is called a TRF (tuned radiofrequency) receiver. In the early days ofradio -before Major Armstrong's super-heterodyne receiver -it was the favoredreceiver. More recently it was used insome garage door opener systems, and,in some high-fidelity systems. It has bet-ter fidelity but is not as sensitive as thesuperhet.

10. D. As you know from readingWDYKAE?, tunnel diodesare still avail-able. I ran a series of discussions ontunnel diodes in recent WDYKAE?articles.


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DESOLDERING TOOL Sells for LESS at...

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1, :Circle (40) on Reply Card

EMC RRProbe capacitor current in computer supphes;other application notes

255 Spectrum Probe 30 KHz to 2.5 MHz $279107 Probe 1 to 100 MHz $249 ($279 extra shielding)

SMITH DESIGN (215) 661-9107207 E.Prospect Ave,N.Wales, PA 19454


'

2!,'75 SPECTRUM PROBE®

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If* Wholesale Electronics, Inc.ORIGINAL PARTS:HITACHI PIONEERGE RCA ZENITH=

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rTo Order BackIssues

Send $3.50 Per Issue(Check, Money Order, Mastercard,

VISA, Discover and AMEX).

Send AllCorrespondence To:

CO Communications76 North BroadwayHicksville, NY 11801

Or Call516-681-2922

FAX 516-681-2926

ORDER YOURBACK ISSUES

TODAY!

Advertiser's Index

CompanyPage

Number

ReaderServiceNumber

AdvertiserHotline

American Reliance 5 31 800/654-9838

Anatek Corporation 63 32 800/999-0304

Andrews Electronics 52 33 800/289-0300

Caig Labs 55 70 619/451-1799

Custom Data Associates 28 35 800/451-0137

Diversified Parts 51 36 800/338-6342

East Coast Transistor 49 6 800/645-3516

Electronic Design Spec./Southgate 13 53 305-720-4497

Fluke Corporation BC 1 800/87FLUKE

Goldstar Precision 11 37 213/404-0101

H.C. Protek 17 3 201/767-7242

H.H. Gregg Appliances 11 317/848-8686

Hameg Instruments 8 72 800/247-1241

Herman Electronics 45 2 800/938-4376

Howard Electronics 68 40 800/394-1984

International Components Corp 63 41 800/645-9154

Iscet 25 817/921-9101

Leader Instruments 3 38,39 800/645-5104

MAT Electronics 50 42 800/628-1118

MCM Electronics 53 43 800/543-4330

MICROCARE 15 44 203/585-7912

Mouser Electronics 25 45 800/992-9943

NESDA 64 817/921-9061

PTS Electronics 44 47 800/844-7871

Parts Express 20 46 800/338-0531

Philips Technical Training IBC 60 615-475-0044

Print Products International 47 48 800/638-2020

Probe Master 11 49 800/772-1519

PRB 46 50 414/473-2151

Sams, Howard & Company 9 51 800/429-7267

Sencore IFC 24 800/SENCORE

Serviceware 22 61 613/521-7391

Smith Design 68 52 215/661-9107

Sperry Tech 68 54 800/228-4338

Tentel 27 55 800/538-6894

Tritronics 48 56 800/638-3328

Wholesale Electronics 68 57 800/351-2233

We'd like to see your company listed here too. Call DianeKlusner at 516/681-2922 to work out an advertisingprogram tailored to suit your needs.


PHILIPSTECHNICAL

AINING

L

Suppli

of Hi -Tech

To order your catalog

or receive the latest

training flyer...

Call, Fax, or Write:

615-475-0044

FAX 615-475-0221

Philips Technical Training

401 East Old Andrew

Johnson Hwy., Box 555,

Jefferson City, TN 37760

III

IAS

WANT TO SERVICEVoted number one in the technical

training industry for nine years

running, Philips will teach you the

"ins and outs" of service.

From diagnosing the problem to

fixing the most complex electrical

systems, our training programs will

give you the fundamental

rj ri r11.

information needed to service a

wide variety of consumer

electronics -)roducts.

Receive han:Is-on training, using

the latest in testing equipment aid

learn valuab e tips and techniques

from our technical experts.

Yo tisfaction is guaranteed!

IMPROVE SERVICE P

ereubier-

of the most time-consuming

responsibilities of a servicer.

With troubleshooting tips in ever{

course, our training programs are

designed to substantially decrease

time spent on the front end and

increase pr )ductivity.

After diagnosing the problem, you

will receive hands-on experience

AND INCREASE PR ITBy increasing the variety of

products serviced, you increase

your potential customer base. By

improving service productivity and

efficiency, you improve customer

satisfaction. All this comes down to

the bottom line-increased profits!

Philips Tec mica! Training courses

are designed with the servicer in

mind. Using the knowledge our

service experts have gained, we will

help your business and your profit

margin gro.v.

LESS.

ODUCTS...

0t -jillJ J J J

repairing this and a variety of

problems for a variety of products,

such as VCRs, computers, monitors,

power supply, and nore!

Our experts will show you how to

find the problem and fix it in

record -breaking time, the first time.

YOUR

ISATISFACTION

IS ALWAYS

GUARANTEED!

JUST A FEW OF THE COURSES COMING YOUR WAY!

Repair:VH ng SystemHigh -Speed VHS VCRTroubleshooting

anicOrder epair:un amen a s o o or Camcorder

,

igital AudioCompact Disc Interactive (CD-i)

ow- s n

Power Supply Repair:4

nan

ply V

VCR Mechanical nanceCamcorder MechanicalMaintenance

r u I

SENCORE es e

r Repair

PHILIPSCircle (60) on Reply Car ,1

Multi -Choice.Ihether you're doing first -level troubleshooting or component -level diagnosis, Fluke meters offer

you one of the widest choice of capabilities and price ranges in the industry. Choices ranging from

the basic Fluke 12 with auto function V-Chek' and Continuity Capture'. 10 the classic Fluke 77

Fluke 83Full -featuredMultimeter$255.00

with Auto Touch Hold" and current measurements.

Fluke 77The classicMultimeter$169.00

To the advanced Fluke 83 with Min/Max/Average recording,

Frequency, Duty Cycle and Input Alert-. Plus a full

line of quality accessories to extend those

capaoilities even further. No matter which Fluke

meter you choose, you can count on precise, reliable, consistent performance year in and

year out. Ilus, strong customer support and product warranties that measure up to any

look to Fluke

for the tools you need to get the job done right.

See your Fluke distributor, or call 1 -800 -87 -FLUKE

for a catalog and the name of the

distributor nearest you.

in the industry. Make the choice

that gives you the most choices.

Fluke 1:Auto-furctionMuhinter$95.00

FLUKE 12 FLUKE 77 FLUKE 83The Fluke meters listed above feature DCAC voltage. resistance.audible continuity and diode test

Capacitance Auto Touch liold4 Auto Touchladandmeasurements Relative modes

V Chek". (auto function) Current measurements Current measurements

lArtMax Record wrth Analog NOM display Analog DVS drsplayRelative Time Stamp

Twolea, warranty Three.year warranq Nee -year warranty

Contnurly Capture' Yellow holster with Flex Yellow holster with FlexStand'. Stand'.

Flaw accuracy 0.9% Basic accuracy 0 3% trout Alen"'

For measurements Capacrlanceto 4800 V -A measurements

Frequency and DutyCycle

lAnAlav Avg Recording

Bow Accuracy 0 3%

John Fluke Mfg. Co.. Inc.P.O Box 9090. Everett. WA 98206For more information call(416) 890.7600 in Canada(2061 356-5500 from other countries

c Copyright 1993. John Fluke Mfg. Co.. Inc. All rightsreserved. Prices subject to change. Suggested U.S. list price.Ad No 00377

FLUKECircle (1 ) on Reply Card

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