ELECTRONIC PARTS E RV C - americanradiohistory.com€¦ · BUSS fuses help you avoid adjust-ments or call-backs that cut into your profits. BUSS fuses can further help you maintain

ELECTRONIC

PARTS

DISTRIBUTORS

SHOW E RV

MAY, 1958

CTHE TECHNICAL JOURNAL OF THE TELEVISION -RADIO TRADE

DETCRYSTAL

ANTENNA

COIL

Tiny three -transistor portable radiowith earphone output.

See circuit analysis, this issue 09-8

AUDIO

TRANSISTOR

EARPHONE

2000 OHMSIMP

2.

C 1 HO Cri V1I'd03I I:1

Brookwood Station Wagon

DEALERS!

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SUPREME PRIZE:

Your choice Ford Del Rio Ranch Wagon, Plymouth

Custom Suburban or Chevrolet Brookwood Station

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200 GRAND PRIZES:

100 Alliance Electric Fry Pans and 100 Sessions

Electric Clocks

1,000 SPECIAL PRIZES:

Crestline Kitchen Tool Sets (seven pieces, coppertone

handles)

6 EXTRA PRIZES:

Alliance Genie Automatic Garage Door Operators

(Radio Control)

IT'S EASY TO WINask your Tenna-Rotor Jobber

to visit us in

ALLIANCE BOOTH No. 321And Hospitality Suite

2105-6-7 and 8

at the Electronics Parts Show

Conrad Hilton HotelChicago, May 19 thru 21

for contest details

THE ALLIANCEMANUFACTURING COMPANY, INC.

(Division of Consolidated Electronics Industries Corp.)Alliance, Ohio

There's a reason Universally designed parts are ofnecessity manufactured to broad tol-erances...and they may not give themaximum in performance andreliability.

Components in a Zenith Radio,Television or High Fidelity Instru-ment are built to be perfectlymatched and balanced for superiorperformance. To keep Zenith sets op-erating at original performance, useZenith quality service components.

When you use Zenith componentsin Zenith sets, it's a custom repairthat both you and your customerscan depend on.

111111111111111111111111111111,You can safely

guarantee Zenith re-pairs when you use dependableZenith components.6uy parts by Zenith

. . backed39 years of leadership in radian-ics exclusively.The quality goes inbefore the Zenith name goes on.

SEE YOUR ZENITH DISTRIBUTOR Q

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ZENITH RADIO CORPORATION PARTS AND ACCESSORIES DIVISION6001 W. Dickens Chicago 39, Illinois

SERVICE, MAY, 1958 I

To 2TY0on a genine Argos Tube Caddy®.... newlydesigned "Pacemaker models for thethrifty buyer ... ruggedly built with Argos

GfG ed/Xe.4"

C

PacergadyEotubA(addy

U

TC-100

$1235

Quickly pays for itself. Holds up to262 tubes, plus tools, meter, etc. Same sizeas Argos "Carry -All" Tube Caddy.

PaegoragleTillstube'eaddy

TC-200

$895Low cost Tube Caddy for quick trips.Holds up to 143 tubes, plus tools, meter, etc.

Same size as Argos Tube Caddy "Junior."

®Registered TM of the Argos Products Co.,originator and sole manufacturer.Ask your Distributor NOW!

or Write Dept. S

rgPRODUCTS COMPANYGENOA, ILLINOIS

Also wall and corner baffles, hi-fi speakerenclosures and kits.

Vol. 27 No. 5 MAY, 1958

27th YEAROF

CONTINUOUSPUBLICATION

1111111111M11111111111MIII1 E RV, immiii,,

THE TECHNICAL JOURNAL OF THE TELEVISION -RADIO TRADEIncluding RADIO MERCHANDISING and TELEVISION MERCHANDISING

Registered U. S. Patent Office

COVER CIRCUIT

All -Transistorized Portable Raaio Receivers (Philco) 10

FEATURES

Editorial 9

All -Transistorized Portable Radio Receivers Robert A. Magnant 10

Installing Hi-Fi Speakers and Enclosures to Improve Sound Systemin Home Robert Miller and Frederic Zeller 14

DC Power Supply for Transistorized Equipment and Low -VoltageDevices R C. Crossley 16

Electronic Parts Show Roundup 18

New Indoor Antenna With Dipole Matching Transformer (Antenna Digest)Rudolph T. Plemich 21

Earth's Field Effects on Color TV Tubes (Tube News) 22

Hi-Fi Amplifiers for TV Receivers (Audio Installation and Service)Perry Sheneman

Signal Distribution Pattern of Ultrahigh Antenna System 28

Repairing Printed -Wiring Board Chassis Leroy Wolff 30

Miniaturized Compensation -Type UHF Tuner Fred J. Kitty 32

Installing Master Motel Antennas Tom Shea 34

Servicing Upright Home Vacuum Cleaners E A. Mueller 40

Association News 44

Books and Catalogs 46

Personnel 47

CIRCUIT DIAGRAMS

Admiral Hi-Fi Sound Amplifier for TV Receivers 24

Electro Products EFB Filtered DC Power Supply 16

Philco T-3 Transistor Portable Radio 10

Philco T-701 Transistor Portable Radio 11

Speaker Crossover Network 14

INDEX TO ADVERTISERS 47

© 1958 1,\ Br a a Davis Publishing Ca., Inc. All rights reserved.

Second -Class mail privileges authorized at New York, N. Y.; additional entry atthe Post Office, Norwalk, Conn.... Subscription price: $2.00 per year ($5.00 for 3years) in the U.S.A. and Canada; 25 cents per copy, $3.00 per year in foreigncountries; 35 cents per copy.

2 SERVICE, MAY, 1958

umminumonni1111111mull1111111`

*euf.r.'t

Editor

Solomon R. Kunis

Associate EditorDavid E. Pearsall II

nintiminiummiiiminnommirim

Consulting Technical EditorsHoward JenningsArnold Gewirtz

Field Editor ( Midwest)Rudolph T. Plemich

Art DirectorAnthony R. Aliffi

Supervisor, Circuit DiagramsMichael D. Bellezza

BUSINESS DEPARTMENT

Advertising ManagerAaron L. Lafer

Assistant Advertising ManagerAstrid Kelly

Business Manager

B. S. Davis

Assistant Business ManagerB. Earley

Circulation ManagerA. Goebel

Assistant Circulation ManagerA. Kiernan

Mailing SupervisorL. Trubia

PACIFIC COAST

Leo Sands, District Manager920 Commercial StreetPalo Alto, CaliforniaTel.: YOrkshire 8-4478

Published Monthly byBryan Davis Publishing Company, Inc.52 Vanderbilt Ave., New York 17, N. Y.

Tel.: Murray Hill 4-0170

B. S. Davis, Pres. A. Goebel, Secy.

.4}P0 5Printed in U.S.A. by

O'Brien Suburban Press, Norwalk, Conn.

Customers Impa,tient?It's full speed ahead

with.ab

CeramicCapacitor

Kits

No delays! It's always smooth sailing when you use Centralabceramic capacitor kits. No extra trips to your distributor, no wastedtime. The units you need are on hand when you need them.

To keep you on an even keel, these heavy gauge steel kits containbalanced inventories of the most frequently used values. Individualvalues are prominently and clearly labeled, so you can locate theHi-Kap you need, instantly. The new rigid plastic package perma-nently separates and protects the units-yet is easily opened toremove a single capacitor.

So don't be left at sea. Ask your distributor about these four time-saving kits-and while you're at it, be sure to get your free copy ofCatalog 30, listing the full line of Centralab capacitors and otherquality components.FREE: $4.75 cabinet (4"x7"x11") with each kit.

D6K-200 Kit -200 Tubular Ceramic BC Hi-Kaps (27 values)DDK-200 Kit -200 Standard Ceramic Disc Hi-Kaps (31 values)TCK-80 Kit- 80 TC (Temp. Compensating) Hi-Kaps (40 values)HVK-150 Kit -150 High Voltage Disc Hi-Kaps (19 values)

Centralab products are listed in COUNTERFACTS, PHOTOFACTS, and

THE RADIO -ELECTRONIC MASTER.

A DIVISION OF GLOBE -UNION, INC.934E E. KEEFE AVE.. MILWAUKEE 1, WIS.In Canada. 804 MI. Pleasant Rd. Toronto, Ontario

'Trademark

SWITCHES PACKAGED ELECTRONIC CIRCUITS CERAMIC CAPACITORS

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SERVICE, MAY, 1958 3

Sylvania comparisons point out-

The big differenceHere's the inside story on why

local "off -brands" don't measure upto Silver Screen 85° standards

IF you're like most dealers, you know off -brandtubes don't have the same quality standards asfirst -line tubes. To help you see how big thedifference is, Sylvania purchased a nationwidesample of sixty 21YP4 A made by 1.9 differentlocal tube makers. These tubes were put throughthe same production tests that all Sylvaniatubes must pass.

Not a single local off -brand passed all 54mechanical and electrical tests! Many of thesewere minor defects making little or no differencein whether or not the tube "lit up." But lookhow loose manufacturing controls can affectthe important features of light output, focus,and life!

LIGHT OUTPUT11-.10%

75%

SILVERSCREEN 85

TUBES

90%-80%

16TUBES

-70%

TUBES 4TUBES

CIVOrOge individuallight output output

"OFF -BRAND"

50%

So far, 39 off -brand tubes have been compared withthe minimum light output of Silver Screen 85. Fiveadditional tubes couldn't even be tested. Eleventubes were less than 90% as bright as the minimumfor Silver Screen 85; 16 were less than 80%; 8 wereless than 70%; and 4 were less than 50% as bright.Since most Silver Screen 85 tubes average as muchas 125% of minimum standards, the differencebecomes even greater. Small wonder that SilverScreen 85 is the easy way to more satisfied customers.

FOCUS

SILVERSCREEN 85

rejected

yould not befocused231%

OFF -BRAND"

stacked upto registered limits on focus voltage. 38.5% wererejected under these limits. Over half of all thoserejected could not be focused in a TV receiver.Small wonder then that "Silver Screen 85" picturesare sharper, brighter, clearer.

LIFE TEST

SILVER SCREEN 85 2100 hours

'OFF -BRAND" 1500 hours 700 hours

I I

10 FAILURES

Nineteen off -brand tubes were placed on Sylvania'sstandard 2000 -hour life test. Chart 3 tells you howfast these tubes developed slow -heating cathodes.Over half, or ten units, failed to go beyond the700 -hour mark. Small wonder then that SilverScreen 85 gives you less troublesome callbacks.

Of all the off -brand tubes tested, Sylvania en-gineers estimate that 43% probably would not haveoperated properly in a TV set. Why gamble yourreputation, customer satisfaction, and success. It'sjust good business to sell up to "first line" picturetubes; Silver Screen 85 picture tubes.


in Picture Tubes!

.thote.iptle,rtnk

rants got. .

C)e'Th

SILVER SCREEN

SYLVAMA [LECTRTC PRODUCTSINC

Take it from Bill Shipley: -Silver Screen 85' consumer advertisingmakes it easy to sell -up to 'first line' picture tubes."

New TV Campaign dramatizes test results . . . sells consumers

up to "first line" picture tubes . . . builds more profitablesales and satisfied customers for dealers everywhere.

Sylvania's fabulous new family, "The Real McCoys," is oneof the top new television shows of the season and has beennamed the "Sleeper of the Year." Week after week, on the"Real McCoys" Sylvania is making millions of set ownersaware of the big difference in picture tubes.

New commercials like the "Brightness Test" are pre -selling consumers on the "first line" performance ofSilver Screen 85.

For dealers everywhere it means more and more customersasking for "Silver Screen 85"-Pre-sold customers makesatisfied customers-strengthening your business reputationand building long-range profitable growth.

Sylvania has designed this powerful new selling tool foryou. Get behind it and sell -up to "first line" SilverScreen 85 picture tubes.

471 SYLVANIA

Highlights of Sylvania's TV"Brightness Test."

"Don't be fooled by picturetubes that look alike - theydon't act alike."

Sylvania's Silver Screen 85 isover twice as bright as this"off -brand" tube

"Insist on a nationally known'Silver Screen 85'-there's oneto fit every make TV "

SYLVANIA ELECTRIC PRODUCTS INC.1740 Broadway, New York 19, N. Y.

In Canada: Sylvania Electric (Canada) Ltd.University Tower Bldg., Montreal

LIGHTING TELEVISION RADIO ELECTRONICS PHOTOGRAPHY ATOMIC ENERGY CHEMISTRY -METALLURGY


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are now in use, accepted as the standard of the industry.Don't stock up on high-fidelity cartridges untilyou've read this vital

THE MISSING LINK to popular -priced stereophonic sound reproductionis here: It's the new Electro-Voice TOTALLY COMPATIBLE StereoCartridge ... plays the new stereo discs superbly ... LP's too ...even better than existing cartridges.By breaking the stereo cartridge cost bottleneck, Electro-Voice has madepopular -priced quality stereo a reality. E -V's ceramic stereo cartridge( Model 21D with .7 mil diamond stylus) sells for only $19.50( Audiophile net).FULL PAGE COLOR ADS & SPREADS IN Popular Electronics,High Fidelity, Hi-Fi & Music Review, Hi-Fi Music at Home, Audio, etc., aretelling the E -V Stereo Story to ALL OF YOUR CUSTOMERS RIGHT NOW.

Here are some of the answers to your questions concerning stereo:Q How does the COMPATIBLE E -V Stereo Cartridgediffer from CONVENTIONAL cartridges?

A It has the ability to play both the new type stereophonicdiscs and conventional records. Inherent in its design isan improved monaural performance. Exclusive design forrumble suppression of 15 db or better will permit the useof Electro-Voice's Stereo Cartridge with any type of changeror transcription player!

Q Are stereo discs compatible with conventional cartridges?

A Most cartridges damage the stereo record. STEREODISCS SHOULD NOT BE PURCHASED UNTIL ANE -V STEREO CARTRIDGE IS INSTALLED. Then, youmay play monaural or stereo discs monaurally. When asecond speaker and amplifier is added, you have stereo-phonic sound.

Q What about modification problems?

A Using an Electro-Voice Stereo Cartridge, which is con-structed so that its output is already corrected to the RIAAcurve, you will not require the equalization of the secondamplifier. Inserting the cartridge is simple. It will fit virtu-ally any standard tone or transcription arm. The additionof a second amplifier and speaker is not complicated.

Q What about record availability?A Recordings by major record manufacturers will be avail-able in mid -1958.

Q What effect will stereo cartridges and records have onpresent equipment?A Only the cartridge will be obsolete. All other componentsare compatible with stereo.

Q What if the customer doesn't have a HI-FI system now. .. should he wait?A NO. He should proceed as before-with one exception:he should use a stereo cartridge initially. When he is readyfor stereo, he need add only a second speaker and amplifier.

Q How do you order the cartridges?

A Contact your Electro-Voice representative or distributor,or write directly to the factory for complete information.Ask for E -V Stereo Model 21D with .7 mil diamond stylusor E -V Stereo Model 26 DST Turnover with .7 mil dia-mond Stereo tip and 3 mil sapphire tip for monaural 78 rpmrecords ($22.50).

IS HERE!

don't stock up on obsolete cartridges ...sell the totally compatible Electra -Voice stereo cartridge

gkeZtreicc° E LECTRO -VOICE, INC.BUCHANAN, MICHIGANCANADA: E -V of Canada Ltd.. 73 Crockford Blvd.. Scarboro, Ontario

FOREMOST IN ELECTRO-ACOUSTICS . . .

Microphones, Phono-Cartridges, High -Fidelity Loudspeakers and Enclosures. Public Address Speakers, MarineInstruments, EVI Professional Electronic Instruments and Military Material.

How to make more money as an independent

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11111111111111111111111111111111111111111111

27th YEAROF

CONTINUOUSPUBLICATION

E RVIITHE TECHNICAL JOURNAL OF THE TELEVISION -RADIO TRADE

11111111111111111111111111111111111111111111

Parts Jobber and Service Man: Mutual Interdependence

IjsT MANY WAYS the Parts Jobber is one of thebest friends the Service Man has. He functionsas a vital link in a national supply chain whichenables the Service industry to obtain needed re-placement parts quickly and efficiently. The factthat most jobbers carry only standard -brand pack-aged parts produced by reputable manufacturershas been a boon to the Service Man, providinghim with reasonable assurance that the part heinstalls will stand up in use.

Many jobber organizations have gone to greatlengths to be helpful to the Service Man. Theyhave provided him with technical information onnew products and developments. Some distribu-tors even maintain laboratories for checking testequipment and components, and the results oftheir investigations are available to the ServiceMan. Parts jobbers also aid Service Men by main-taining proper and business -like credit relationswith them and by joint efforts in promotion andadvertising campaigns.

It is for these reasons that SERVICE salutes theParts Jobber on the occasion of the 21st annualElectronic Parts Distributors Show which is beingheld in Chicago on May 19-21. We extend ourbest wishes to the Electronic Industries Associa-tion, the National Electronic Distributors Associa-tion, the Association of Electronic Parts andEquipment Manufacturers and the other sponsor-ing organizations and urge them to continue topromote the interests of the Service Man as well astheir own interests in a spirit of mutual interde-pendence.

Friendship is a two-way street, and the PartsJobber depends on the Service Man, too. It isonly by working together to handle and resolvethe problems which face both mutually that theService Industry and the Parts Distributor canassure a bright future for both groups.

THE LAST WORD on color is that this field is mov-ing forward at a far faster pace than most peoplerealize. Addressing shareholders at RCA's 39thannual meeting early this month, president JohnL. Burns pointed out that color television con-tinues to advance not only in programming butalso in merchandising.

Sales of color sets to consumers are running wellahead of last year, he reported, and intensive colorpromotions in many parts of the country are pro-ducing excellent results. Dealers are becomingconvinced that their greatest future profits will berealized in color TV receivers.

The quality and performance of color TV setsimproved considerably in 1958, Mr. Burns stated,and he looks forward to future increases in salesduring the rest of the year. Progressive ServiceMen would be well advised to prepare now fora demand for color TV servicing that is sure tocome sooner than most of us realize.

* * *

ANOTHER FIELD which is also moving rapidly for-ward is mobile radio systems. Despite generallyunfavorable economic conditions, the mobile radiobusiness has continued to grow at a rapid paceand those in a position to know believe this isonly the beginning.

An indication of the expected growth in thisfield is contained in the testimony before a HouseCommittee by Curtis Plummer, chief of FCC'sSafety and Special Services Bureau. Mr. Plummerpredicted an increase of 100,000 stations in thecoming fiscal year.

The 425,000 stations now licensed, he pointedout, use approximately one and a half million fixedand mobile stations. Here is another activitywhich bears watching by the alert Service Man.


All -Transistorized Portable

Radio Receivers [See Front Cover]

New Series Utilizes 3 to 9 Transistors With Stable Temperature Parameters

by ROBERT A. MAGNANTGroup Supervisor, Engineering Dept., Philco Corp.

TEMPERATURE STABILITY is always anessential part of good radio design,and it becomes especially importantin a transistor radio. One of the bestways to insure good temperature sta-bility is to choose transistors in whichthe temperature -dependent para-meters are of the proper value to havelittle effect on the circuit operation.By the use of surface barrier transis-tors in the rf, if and detector stages,especially good results are obtained inthis respect. Another method is to pro-vide current stabilization, usually bymeans of an emitter resistor. Mostaudio stages require this type of tem-perature stabilization because of high-er operating temperatures generatedby the higher power levels.

A new line of transistorized port-able radios' has just been placed onthe market which makes use of bothsystems to insure stability within thedesired temperature range. The setsrange in size from a tiny three -tran-sistor model to a nine -transistor all-

wave portable. A description of thecircuitry utilized in some of these setsfollows.

Three -Transistor Portable

The smallest unit' in the line, ap-proximately as large as a king-sizedpack of cigarettes is shown in Fig. 2and illustrated schematically on thecover and in Fig. 1. It will fit intoa shirt or vest pocket, and an ear-phone attachment permits the ownerto use the set without disturbing otherpeople in the area.

This model uses two tuned rf stagesfollowed by a diode detector and anaudio output stage which drives theearphone. Because of the low powerrequirements of the earphone, it waspossible to use a battery voltage of

'Manufactured by Philco Corp. 2Philcomodel T-3. 3Philco model T-701.

only 2.6 volts. Since the current drainis also small, it was decided to usesmall mercury cells which are con-sistent with the size of package butwhich would give a reasonable bat-tery life. For this reason two P630cells were used which allow approxi-mately 150 hours of use.

One of the major problems in anyradio is that of obtaining good stagetracking without elaborate precau-tions which add to the cost. This washandled on this set by use of a dualtuning knob which provides bothcoarse and fine tuning. The antennaand first rf tuning condensers haveseparate knobs which are looselycoupled mechanically. This permitsthem to be rotated together easilyand still provide individual adjust-ment of each condenser so that bothstages may be perfectly tuned to theincoming signal. The exact tuningobtained by this dual -knob methodoften surpasses that achieved on

more expensive sets with standardone -knob tuning systems.

After the incoming signal is am-plified by the tuned antenna and firstrf stage it is fed to a broad -bandsecond rf stage for further amplifica-tion and thence to a diode detector.The detected audio is then fed to theaudio amplifier which raises the levelhigh enough to drive the earphone.

A newer version of this model willsoon be on the market with improvedsensitivity. This is being achieved inthe same package size by the addi-tion of audio refiexing to the first rfstage. Reflexing is the principle ofusing one transistor to amplify signalsof two different frequencies. In thiscase, the detected audio signal is fedback to the first rf stage where it isfurther amplified before being appliedto the audio output stage, thus con-siderably improving the sensitivity ofthe receiver.

Seven -Transistor Portable

A seven -transistor radio3 which op-erates as a high-performance portable

AX MIA

CO I.

DOT

CITSTAL

1ST I f 200 AR1303 306

'3 -IS?MYR/

, .16

-ADa a1

a I

56_r_ _JII -nr

AUDIO

TRANSISTOR

A

J/

I I

'MSC,

51F

L

22,000.ows

50000.5R5

EADPIIONE

1000 0115'NP

FIG. 1: SCHEMATIC DIAGRAM of Philco model T-3 portable radio receiver whichutilizes only three transistors in the entire circuit.


FIG. 2: THREE -TRANSISTOR portableradio is approximately same size as pack

of king-sized cigarettes.

and yet has sufficient power outputto take the place of conventional line -powered table model radios is alsoincluded in this series. This set,shown schematically in Fig. 4, has a200 mw class B push-pull output sys-tem with a heavy -magnet 4 -in. speak-er and operates from four standardD -size flashlight batteries. Since a

heavy -magnet speaker is considerablymore efficient in converting electricalpower to accoustical power, this 200mw system will provide a sound vol-ume equal to that produced by setswith much greater power output butemploying a light -magnet speaker.

Dual Antenna System

To take full advantage of a goodoutput system it is necessary to havesufficient gain ahead of it to receive

all the desired stations without noiseinterference. This is greatly aided bythe use of the dual Magnecor scan-tenna used on this set. By properphasing of the coils on the dual Mag-nccor during assembly, considerablyinure power is obtained from a givenbroadcast signal than is possible withsingle antennas usually used in thissize of radio.

Transistor Stages

In addition to the antenna, seventransistors are used in the set to pro-vide the necessary gain. The systemmakeup is as follows: converter stage,two if stages, a transistor power de-tector, an audio amplifier stage, andthe push-pull output stage. The op-eration of these stages is conventional,except that there are four tuned ifcircuits instead of the usual three toprovide better adjacent channel at-tenuation. The transistor detectorprovides both detection and amplifi-cation and is an important factor inthe overall gain picture.

Nine -Transistor Portable

The largest set in this series is

a nine -transistor all -wave portableradio.' It has seven bands includingthe broadcast band, a 2 to 4 mc band,a 4 to 8 mc band and four spreadbands at 16, 19, 25 and 31 meters.This portable set is shown in Fig. 3.

The set uses a tuned rf stage, aseparate oscillator which has its ownpower supply for frequency stability,a mixer stage, two if stages, a tran-sistor detector stage, an audio ampli-fier stage, and a push-pull class Boutput stage. The power supply is 6volts, provided by four standardD -size flashlight batteries, for themain part of the set. Two separateflashlight batteries for collector andemitter stabilization of the oscillator

FIG. 3: PH ILCO'S ALL -WAVE PORTABLEmodel T-9 utilizes nine tranistors and ispowered by D -size flashlight batteries.

are also included. The power outputis 250 mw into a heavy magnet 4 -inchspeaker.

Four -Transistor Model

There is also a coat pocket or pursesize model' employing four transistorsand powered by four pen -light cells.The Magnecor antenna is followed bya converter stage, and two stages ofif amplification. The if signal is de-modulated by a diode detector andthe resulting audio signal is reflexedin the second if stage which takes theplace of an audio driver. This am-plified audio signal is then applied tothe audio output stage for sufficientpower amplification to drive thespeaker. This set has a class A outputstage which provides 25 mw to a

2% -in. speaker.---

*Philco model T-700. 'Philco model T-9."Philco model T-4.

(1033

CONVERTER

15 000

OHMS

8200OHMS

01

MFD

2700OHMS

r --3f- 11233

15T IT AWL r

Flo of61

I

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11232

21013 AMPL r

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OHMS t1000011--ANVIr-- MS OHMS

)100010001200 g2po

OHMS OHMS OHMS (1M5

J

T1033

IND DE1

2200144S

1ST AUDIO

MFD

4000CONS

20MFD

SOOOHMS

220OHMS

100UFO

01l2 043100MPS

OUTPUT (MATCHED SIR)

--H°' MID

OHMOHMS

13

FIG. 4: CIRCUIT DIAGRAM of seven -transistor Philco model T-701 portable radio.

SERVICE, MAY, 1958 II

EVEN THOUGH THE DADDY OF

3 reasons why there are

NO printed circuits in Zenith TV chassis

1111"standard HANDcrafted circuitry means:

1 LESS SERVICE HEADACHES

INTO standard HANDcrafted circuitry means:

9 EASIER SERVICING FOR DEALER

L AND SERVICEMAN ALIKE

standard HANDcrafted circuitry means -lei MORE SATISFIED CUSTOMERS

FOR ZENITH DEALERS

We think it's worth the extra cost and extra careof HANDcrafted standard circuitry to get the best performance andleast service headaches and so do thousands of dealers who wouldsooner sell customer satisfaction than a price tag.

ZENITH RADIO CORPORATIONChicago 39, Illinois

The quality goes in before the Zenith name goes on.Backed by 39 years of leadership in radionics exclusively.Also makers of Radio, High Fidelity Instruments and fine Hearing Aids.

yareirawAr


PRINTED CIRCUITRY IS HEAD OF

ZENITH'S RESEARCH DEPT; THERE'S

NO PRINTEDCIRCUITRYIN ZENITH

TV CHASSIS*Even though Dr. Alexander Ellett, head of Zenith's re-search department, is recognized as the daddy of printedcircuitry through his work on radio proximity fuses, stillZenith uses no printed circuitry in its TV chassis because itmeans more service headaches and often causes servicedelays.

QUALI TAT BY

/,FAITHThe Royalty of Television


Installing Hi-Fi Speakers and Enclosures

To Improve Sound System in Homeby ROBERT MILLER*and FREDERIC ZELLER

SERVICE MEN are frequently askedby their customers if it is possible tobuild a hi-fi installation which willutilize standard radio or TV receiversnow functioning in their homes. Theanswer is that very often a startlingimprovement can be made in thesound quality by modifying or addingto the speaker in the original equip-ment, and that this constitutes a goodstart toward a more fully developedhigh fidelity system.

The weakest link in console radios,phonographs, TV sets and packagedhi-fi sets is usually the speaker. Almostinvariably the amplifier circuit usedin these units is capable of producinga much closer approximation to hi-fithan can the commercial loudspeakerswhich the manufacturer is forced touse in order to keep his price at acompetitive level. Considerably bettersound quality can often be obtainedby the substitution or addition of hi-filoudspeakers. This may be done inmany different ways, depending onthe requirements and budget of thecustomer.

The simplest and least expensiveway is the addition of a simple ca-pacitor network, balance control andtweeter (Fig. 1) to a system that hasa single large -cone speaker. Mostspeakers of this type tend to be de-ficient in the high -frequency rangeabove 5000 cps.

The inclusion of a 4-mtd capacitorwith an 8 -ohm tweeter will give acrossover frequency of 5000 cps andimmediately add surprising highs andbrilliance to the reproduction. Thebalance control allows adjustment oftweeter level to suit personal listening

°Technical Service Manager, UniversityLoudspeakers, Inc.

FIG. 1: CIRCUIT DIAGRAM of simplecapacitor network.

FIG. 2: TYPICAL HORN TWEETER is shown at left and a crossover network withbalance control at right.

taste. For mole accurate tiequencyseparation, standard networks' areavailable from various high fidelityspeaker manufacturers. A typical horntweeter and a crossover network withbalance control are shown in Fig. 2.

Although the addition of a tweeterresults in greater sharpness and clar-ity, response will be still further im-proved if a wide -range hi-fi speakerwere substituted for the commercialone in the set. By itself, a wide -rangespeaker should be capable of handlingfrequencies from low bass up to13,000 cycles, and with tweeter andnetwork added the range is increasedwell beyond 15,000.

While some of the amplifiers usedin commercial equipment have a se-lection of output impedance tapsavailable, most have a basic outputimpedance of 3-4 ohms. Matchingsuch amplifiers with 8 -ohm high-fidelity speakers is no problem, how-ever, since a slight mismatch is oftenpermissible. A slight loss in powermay sometimes result, but the higherefficiency of the new speaker willusually compensate for this. Whenthe power loss seems too great, andquality of reproduction seems tosuffer, the use of a 4 -ohm to 8 -ohmline matching transformer should beutilized.

When an 8 -ohm tweeter is usedwith 3 -or -4 -ohm original equipmentspeaker, more energy will be passedto the cone speaker, which has alower impedance. This can create adesirable situation in that the listenerfrequently wants more bass than mostsystems deliver. Since the addedhorn -type tweeter has inherently

greater efficiency, tweeter output willstill be sufficient to balance the in-creased energy from the cone woofer.This sometimes eliminates the needfor a balance control on the tweeter.

Where space is cramped or cuttingan additional hole for a tweeter isdifficult, a coaxial or three-way speak-er provides a good solution. Theseare available in 8 -inch to 15 -inchmodels and usually have built-in net-works. The best type of coaxialspeaker usually consists of a largecone woofer for bass and middlerange and a separately driven horn -loaded tweeter for high -frequency re-production. (Fig. 3). In this type ofcoaxial design there is no interactionbetween the two components, andquality of reproduction can be asgood as that of most comparable two -speaker systems.

One of the greatest difficulties ex-perienced with any speaker is the re-production of bass notes. The partplayed by the enclosure in assistinga speaker to reproduce low frequen-cies is often overlooked. A speakeroperating in open air without any en-closure does not reproduce any bass,even though low -frequency conemovement is readily observed. A"short circuit" exists between the frontand rear of the speaker cone, andwhen the path length from the conefront to cone rear is of a distanceequivalent to the speaker diameter,low frequencies are cancelled beforethe acoustic waves can form sufficientlength to be heard.

Since the wave length of a 50 -cycle

'Such as University model N1 shownin Fig. 2.


note is approximately 22 feet long, itbecomes immediately apparent that asimple baffle board measuring 11 feetby 11 feet produces a strongly audible50 -cycle note because the path lengthof sound from speaker front to speak-er rear is 22 feet. Folding this baffleboard produces a correspondinglysmaller, open -backed box, and addinga back panel completes the basicclosed box or infinite baffle which isthe simplest of speaker enclosures.

Bass Reflex Port

In order to obtain good results froma 12 -inch speaker, an infinite bafflewould have to be at least 8 and 15cubic feet, -respectively. However, itis possible to obtain excellent resultsfrom a much smaller more convenientenclosure by making use of variousdesign approaches. Perhaps the sim-plest and most extensively used ofthese is the phase -inversion method.This provides an additional openingin the baffle board on which thespeaker is mounted-called a bassreflex port. Further, the interior ofthe enclosure is heavily padded to ab-sorb the higher frequencies. The port,therefore, allows the rear radiationsof lower frequency to reinforce thedirectly radiated sound to provide anacoustic bass boost. The size of the

CROSSOVERNETWORK

COMPONENTS

DRIVERFOR

TWEETERHORN

DUSTCOVER

bass reflex port depends on the reso-nant frequency of the speaker em-ployed and on the cubic capacity ofthe enclosure. Precise information canusually be obtained from the speakermanufacturer.

Commercial equipment usually en-countered by Service Men use open -back enclosures. This is true of evenmany of the so-called hi-fi packagedsets. Obviously, this results in basscancellation at some point in the fre-quency range, the precise point de-pending on the path length of soundfrom the front to the rear of thespeaker. To compensate for this theoriginal speaker is often designed witha bump in the higher bass range tocreate an illusion of deeper bass, andso circumvent the higher cost of asealed and properly modified enclo-sure.

Some larger commercial radio, TVand phonograph cabinets of the con-sole or floor variety lend themselvesto complete "sealing" of the speakerenclosure space and Service Men haveoften done just that to improve thesound quality when substituting hi-fispeakers. Obviously, many of theseenclosures are not of optimum sizefor maximum performance. Neverthe-less substantially improved reproduc-tion is possible by sealing available

CENTERINGDEVICE

( SPIDER

"W' MAGNET

WOOFERVOICECOIL

WOOFERCONE

RECIPROCATINGFLARES

TWEETERHORN

SPEAKERBASKET

H.F. LEVELCONTROL

FIG. 3: COAXIAL SPEAKER consisting of large cone woofer for bass and middlerange and a horn -loaded tweeter for high frequencies.

(All photographs courtesy of University Loudspeakers, 1n,

FIG. 4: PRE -ASSEMBLED UNIT completewith speakers and network.

space wherever practicable to makean airtight enclosure.

Before this is done, however, it isadvisable to strengthen the corners ofthe future enclosure by the additionof .71 -inch x 3/4 -inch cleats. Any paneladded for sealing should be of 71 -inchminimum thickness plywood. Theadded panels should be secured witha screw in every corner and additionalscrews along the edges no more than4 in. apart. A layer of fibreglas atleast 1 -inch thick should be used tocover all of the back panel, all ofone side panel, and all of the toppanel. For optimum lower frequencyresponse, a bass reflex port as dis-cussed earlier should be cut.

Certain higher quality packagedhi-fi units may already have some sortof an enclosure. If such a system failsto meet the specifications previouslygiven, improvement of the enclosureor the substitution or addition of bet-ter speakers will result in improvedsound quality. The ideal solution ofcourse, is to hook up a separate en-closure complete with hi-fi speakersto the existing radio, TV or phono-graph. It is important to note in thisconnection that most commercialradio, TV, phonographs have a lowoutput power rating, sometimes nomore than watts, so that a highefficiency speaker system should beemployed.

There are several methods of add-ing a separate enclosure. The simplestway is to simply buy a pre -assembledunit complete with speakers and net-works, ready to connect. (Fig. 4).These units often make attractivepieces of furniture which can be ac-commodated either in a corner oragainst the wall of a room.

Another method is to buy an en-closure, choose a suitable speaker orspeakers, and then mount and con-nect them. This has the advantagefor the customer in that he can startxvith a single w ide-range speaker andprogressively expand his system ac-cording to taste and budget.


DC Power Supply For Transistorized

Equipment and Low -Voltage Devicesby R. C. CROSSLEY

Electro Products Laboratories

ORIGINALLY DESIGNED to meet theneeds of an engineer for transistordesign work, this power supply hasbecome a service instrument becauseof its acceptance and usefulness inthe field. The unit° is a dual -rangepower supply, 0-32 v (at continuouscurrents up to 40 amps) and 0.16 v(at continuous currents up to 8

amps), with both ranges continuouslyand smoothly variable over bothranges. Important to the design en-gineer and useful to the Service Manis the maximum rms ripple voltagefigure of less than 0.1%.

Utilizing a patented method of con-duction cooling, the heat normallygenerated during operation of theselenium rectifiers is more efficientlydissipated by mounting the rectifiersdirectly to the sides of the cabinet.

louvers areprovided at the top of the unit, asshown in Fig. 1.

Component Features

Component -wise, the dc power sup-ply, illustrated schematically in Fig.2, has a line filter which minimizesthe effects of transient voltages thatmight be carried on the supply line.Also included is a heavy-duty carbonbrush control transformer for smoothadjustment of the output voltage andD'Asonval meters. A full -wave sele-nium rectifier bridge feeds a two -sec-tion /c filter, each with its own bleederresistor. An ammeter monitors the

*Electro Products model EFB.

.014TPUT-

f-i* vOtti, Amos NA),

e,19.01.11,AMPS MAL

tensMA NI 11 111.

a

.,604wpeifttVI

FIG. 1: DC POWER SUPPLY suitable for servicing transistorized and other low -voltageequipment.

high -side output current and a dual -range voltmeter across the arm of thebridge reads the output voltage.

Controls

The single -knob control, shown inFig. 1, determines increments ontransformer T1 for output voltage ad-justment. The toggle switch, used toselect the desired output voltage -cur-rent range, automatically selects thecorresponding voltmeter scale.

Two square clear - plastic panelmeters with D'Arsonval movementsassure accuracy in output voltage andcurrent readings. Clearly labeled andcolor -coded multi -purpose output ter-minals are located on the front panel.

FIG. 2: SCHEMATIC DIAGRAM of Electro model EFB filtered dc power supply.

A 3 -amp ac line fuse also is easilyaccessable from the panel. Perhapsequally important and often over-looked is the rating information print-ed directly on the front panel. Thisenables anyone not familiar with theequipment to know exactly the loadthe power supply can safely handle.This information is printed just belowthe dc ammeter.

Servicing Features

To anyone interested in servicingnot only transistorized equipment butalso relays, solenoids, telephone cir-cuits and other low -voltage devices,the output performance characteristicsare extremely useful. These are graph-ically illustrated in Figs. 3 and 4.

A separate set of curves for eachof the two output voltage rangescompletely describes dc voltage, dccurrent and rms ripple voltages. Forexample, when the user is drawing3 amps at any voltage on the 0-32 voutput range, the guaranteed maxi-mum ac ripple voltage present at theoutput terminals will not exceed 7.7my. Also, should the user be drawing

(Continued on page 29)


p

spnasurruliTIKe.1.00 M stoMt

PacTel

AN 4,IA

10

c.

'''' .14' ,i'`' ''"'4

01111011 flIONCTS WIMP

1,00110,

4114,1 =NIx.

40.11

measures all

CAPACITAN

Measures up to2000 a in five ov-erlapping ranges. . . including anaccurate 1 to 100giif range, exclu-sive with Sprague.

2POWER

FACTOR

Power factor ofelectrolytic capaci-tors is measured bythe highly accuratebridge method.Reads up to 55%in three ranges forconvenience inmeasurement.

NEW TO -5 TEL-OHMIKEcapacitor analyzer

3LEAKAGE

CURRENT

Leakage current ofelectrolytics ismeasured directlyon the meter, withexact rated voltageup to 600 v. ap-plied from contin-uously adjustablepower supply.Two ranges -0-6-60 ma.

The NEW TO -5 TEL-OHMIKE CapacitorAnalyzer is one of the fastest and surest ways ofmeasuring ... capacitance, power factor, leak-age current, insulation resistance, and turnsratio. This compact, easy -to -use instrument hasthe highest accuracy of any instrument of itstype available to the service trade.

New jumbo dial makes meter reading easy.Special color -keyed pushbuttons permit instantrange selection . . . and allow automaticsafety discharge of capacitors after testing.Magic -eye tube simplifies bridge balancing forcapacitance and power factor measurements.

. . plus

Insulation resist-ance of paper, ce-ramic, and micacapacitors is readdirectly on meter

. up to 20,000megohms.

extrafeatureTURNS RATIO

In addition to itsfunction as a com-plete capacitor an-alyzer, the TO -5also measures theturns ratio ofpower and audiotransformers.

SEE THE NEW TO -5 TEL-OHMIKE INACTION . . . AT YOUR DISTRIBUTOR!This 4 -in -1 test instrument is only 8"A" high, 14%" wide,and 6%" deep ... weighs a mere 121/2 pounds. The com-plete price for ...MODEL TO -5 (115 VAC/50-60 cy) .. Only $0 390ntAlso available: Model TO.5X for 115.230 V/25-60 cy. . $89.90 net

Model TP-5RM for rack mounting $93.90 net

SPRAGUEuorld's largest capacitor manufacturer

SPRAGUE PRODUCTS COMPANY, DISTRIBUTORS' DIVISION OF SPRAGUE ELECTRIC COMPANY, NORTH ADAMS, MASS.


FIG. 1: CBS-HYTRON industrial tube line.

FIG. 2: GENERAL INSTRUMENT PTStop -hat silicon rectifier.

FIG. 3: INTERNATIONAL RECTIFIERsilicon voltage regulator and reference

diodes.

FIG. 4: CLAROSTAT miniature carbonpotentiometer.

Electronic PartsPrecision and Misohituri=ell Equipment

Featured at the HiltonTHE ELECTRONIC Parts DistributorsShow, being held in Chicago at theConrad Hilton hotel from May 19ththrough 21st, shows a shift in the in-dustry toward precision and indus-trial -type components and equipment,as well as further emphasis on minia-turization. Many manufacturers in theaudio field are exhibiting stereophonicequipment which has sprung intoovernight prominence.

Replacement components have beenrefined or entirely redesigned to pro-vide greater reliability and to makethe job of installation easier. Newpackaging methods have beenadopted throughout the industry tomake the stocking and selection ofreplacement parts faster and moreconvenient.

Among tube manufacturers theproduction trend points toward theincreasing importance of industrialand special purpose tubes (Fig. 1) inaddition to further refinements inoriginal equipment and replacementunits.

In the rectifier field a wide varietyof silicon diode types are beingstressed. Units are being manufac-tured in top -hat, double -anode, multi-ple -junction high -voltage and refer-ence element types (Figs. 2, 3). Aminiaturized silicon voltage variablecapacitor is being shown by Interna-tional Rectifier Corporation.

All-purpose high -density seleniumreplacement rectifiers are featured bythe General Instrument DistributorDivision. A series of selenium contactprotectors for arc suppression in accircuits is also being introduced by In-ternational Rectifier Corporation.

A self-service merchandising dis-

FIG. 5: ALLIANCE T-12 Tenna-Rotor.

play of Divap ceramic capacitorswith 5 -of -a -kind units packaged on a3 x 5 card is featured in the P. R. Mal-lory and Company booth. Display isbeing used to introduce the units tothe service trade.

Clarostat Manufacturing Company'sexhibit features many precision unitsin addition to their standard line ofreplacement resistors and potenti-ometers (Fig. 4). Also on display isthe Greenohm V viterous enamelpower resistor line.

A compact flat-loopstick radio re-placement antenna designed forgreater signal pickup and increasedselectivity is being shown by SuperexElectronics Corporation.

In the television antenna field theFinney Company is featuring its twin-

driven Geomatic models, custom -de-signed models for particular areas,and a high -power antenna developedfor tracking of earth satellites.

A new parabolic uhf antenna (seepage 28) is featured in the ChannelMaster exhibit.

Trio Manufacturing Company isfeaturing their Colorite antenna de-signed specifically for b -w and colorreception in metropolitan and sub-urban areas.

An antenna rotor (Fig. 5) featur-ing a direction indicator which auto-matically gives compass direction ofantenna is being introduced by TheAlliance Manufacturing Company.

Blonder -Tongue Laboratories areshowing an all -channel vhf two -setbooster (Fig. 6) designed to bring insharper and clearer pictures. Unitamplifies signal on one or two setswhether both or just one set is inoperation.

MODEL 8-23

2 -SET BOOSTER

FIG. 6: BLONDER -TONGUE 6-23 two -setbooster.

4,


Show Roundupand Stereo Components to BeHotel in Chicago

An extra -heavy adjustable auto ra-dio antenna Super 8 with 8 -ballmount that allows adjustment up to35 degrees is being exhibited byWard Products Corporation. Unit hasa 54 -inch lead cable.

Electro Products Laboratories isfeaturing a dual-purpose de powersupply kit (Fig. 7) for servicing tran-sistor portable radios and 12 -volt autosets.

Fourteen work -bench hook-up wiredispenser kits (Fig. 8), each contain-ing a metal dispenser rack and anassortment of popular sizes and colorsof vinyl, vinyl -nylon, textile, or tefloninsulated hook-up wires are being in-troduced by Belden ManufacturingCompany. Kits are available in sizes20 through 26 and contain either 5, 8or 10 different colored spools.

Vaco Products Company is intro-ducing its Red Cap screwdriver line(Fig. 9) with tempered steel bladesand red, shockproof plastic handles.Seven units in the line are a No. 1Phillips with a 3 -inch blade, No. 2Phillips with a 4 -inch blade, 3/16 -inch round blade in both 4 and 6 -inchlengths, ;.i-inch round blade in 4 and6 -inch lengths, and a 5/16 inch roundblade 6 inches long.

A knee -hole work bench with eightdrawer -cabinets (Fig. 10) is includedin the Equipto line. More than 16bench and cabinet units are availablein a wide variety of combinations.

Jensen Industries is exhibiting anew line of 32 phono cartridges (Fig.11) designed to replace 80% of exist-ing units. Cartridges feature a simpli-fied needle changing method and abuilt-in needle guard.

A low -mass damped true pivot

FIG. 7: ELECTRO-PRODUCTS KPS-2transistor i power supply kit.

stylus arm construction is featured inthe RG 666 phono cartridge shown bythe Recoton Corporation.

Ronette Sales Corporation is ex-hibiting its Binofluid stereophonic car-tridge said to be compatable withboth monaural and stereo discs. Unitcan be used as a replacement car-tridge in existing phonos.

A pictorial self-service replacement -needle catalog designed for the ser-vicing field is being introduced by theDuotone Company. Featured in thecatalog are photos of nearly all phono-graph models produced since the in-troduction of long-playing records.

American Microphone Manufactur-ing Company is featuring a tape rec-order -conference microphone ( Fig.12) with a push button that can bedepressed to talk or switched on per-manently for conference use. Includedis a clip -on stand for resting the uniton conference tables. Stand can alsobe used as a lavalier to support themicrophone in speaking position onthe chest.

A hi-fi speaker system in a low-boy enclosure is being exhibited byUniversity Loudspeakers. Model isavailable with two different three-wayspeaker systems or as an enclosureonly.

David Bogen Company is introduc-ing a stereophonic adapter amplifier,ST 10, designed to convert existingmonaural systems for two -channel use.Unit is said to require only an extraspeaker to achieve stereophonic repro-duction. Adapter can be used with atape recorder (with proper playbackheads); magnetic, crystal or ceramicstereo cartridges; or with an FM -AMstereo tuner.

FIG. 9: VACO Red Cap screw driver line.

FIG. 10: EQUIPTO work bench.

FIG. 11: JENSEN INDUSTRIES replace-ment cartridge.

FIG. 8: BELDEN hook-up wire dispenser FIG. 12: AMERICAN MICROPHONE 204kit. tape recorder -conference mike.


NEWCOMPLETE

ANT.

* *5 MC DISCRIMINATOR AUDIOor

AMP.IF RATIO DETECTOR

RFAMP

1stIF

RFOSC.

2nd 3rdIF IF

SYNC.

VIDEO VIDEODET. AMP.

VERTICALOSC.

HORIZ.OSC.

VERTICALOUTPUT

HORIZ.OUTPUT

DAMPER

SPKR.

AUDIOOUTPUT

HI -VOLTAGERECTI FIER

UNIQUE NEW SIGNAL -INJECTION TECHNIQUE

Saves TV Trouble -Shooting Time and WorkR.F.

I.F.

VIDEO

SYNC

SWEEP CIRCUITDRIVING PULSES

INTERMITTENTS

AUDIO

Supplies complete r.f. and i.f. signals withvideo and audio modulation to quickly trou-bleshoot each stage in each of the sectionsof the TV receiver. Enables you to check ther.f. sensitivity and AGC settings of TVreceivers.

Reproduces a complete test pattern on thescreen of the TV picture tube and injectssignals into each video stage of the TV re-ceiver for fast, visual trouble -shooting andcorrection-anywhere, anytime, Makes it easyto check bandwidth, resolution, shading andcontrast capabilities of the TV set.

Provides composite signal, sync positive andnegative.

Provides separate vertical and horizontaldriving pulses for trouble -shooting deflectioncircuits.

Test signal injection also aids in locating in-termittent troubles.

Provides a 4.5 me sound channel, FM mod-ulated with approximately 25 kc deviation.(This audio carrier is modulated either froma built-in 400 cycle tone generator, or fromyour own external audio source.) Injectionof the 400 cycle tone signal simplifies trou-ble -shooting of the audio section.

COLOR Enables you to trouble -shoot and signal tracecolor circuits in color TV sets.Generates white dot and crosshatchpatterns on the TV screen for colorTV convergence adjustments.Generates full color rainbow pat-tern of orange, red, magenta, blue,cyan, green to test color sync cir-cuits, check range of hue control,align color demodulators, etc.

SET Enables you to check and adjust the verticalADJUSTMENT and horizontal linearity, size and aspect

ratio of television receivers.

Canada: Atlas Radio Corp., 50 Wingold, Toronto 10, Ont.

TELEVISION

ANALYSTtest each stage

SEPARATELY

ILI,S1010 'ANALYST

NEW

griMODEL1075

and watch theresult on theTV set itself

13gTELE VISIONANALYST

0 0 0 Eli'Wa

C

diD

QUICK, DIRECT, COMPLETE TV TROUBLE -SHOOTING

Now, by point-to-point signal injection andtest pattern reproduction, you can easily trouble -shootand signal trace any stage throughout thevideo, audio and sweep sections of black & whiteand color TV receivers. With the remarkablenew Model 1075 B&K TELEVISION ANALYST, you canquickly isolate and diagnose TV troubles( including intermittents). By use of the generatedtest pattern, you can actually see the conditiondirectly on the picture tube of the television set itself.No external scope is needed. The TELEVISIONANALYST iS practically a completeTV service shop in one instrument! Net, $25995

See your B&K Distributor or write for Bulletin API? -S

B a K MANUFACTURING CO.3726 N. Southport Ave. Chicago 13,

export: Empire Exporters, 458 Broadway, New York 13. U.S. A,


New Indoor Antenna With Dipole Matching Transformer

UHF -VHF ANTENNA DIGESTDESIGN APPLICATION INSTALLATION SERVICE

by RUDOLPH T. PLEMICH

IN THE EARLY days of television, pri-mary signal areas generally were in-adequate to provide sufficient signalstrength for TV sets in large metro-politan areas without the use of out-door antennas. With the greatlyincreased number of TV receivers,outdoor antenna roof space becameincreasingly difficult to obtain, espe-cially in large apartment buildings,and was often a source of friction be-tween landlord and tenant. For thesereasons many set owners in large citieswere forced to operate with indoorantennas, though the results wererarely as satisfactory as with an out-door installation.

In the last few years, however,primary signal areas have been ex-panding as TV transmitting stationshave increased their output, raised theheight of transmitting antennas orboth. As the effective radiated powerof TV stations has increased, the re-sults obtained with indoor antennashave shown corresponding improve-ment, and their use has even becomepossible in what were formerly sec-ondary and fringe signal areas.

Most indoor antennas in use today,however, have a number of objection-able features. The styling is oftenbulky, they have long dipole elements,and often require channel switching.These have been a source of constantannoyance to set owners and areprobably largely responsible for limit-ing the spread of indoor -antenna use.

A new indoor antenna, designatedthe Vi -Fig°, has been developedrecently which eliminates these ob-jections. This antenna is shown inFig. 1 with the dipole elements fully

`Registered trade nark, Amphend Corp.

extended, with the elements tele-scoped and folded into the case, andwith the roll -up dust cover closed.When fully closed, the indoor antennameasures $13 in. long, 3 in. wide, and1 in. high.

Dipole Matching Transformer

Physically, the dipole is about thesimplest type of antenna. It is a well-known fact that a simple dipole hasa characteristic impedance of 72 -ohmswhile the nominal TV set input isusually 300 -ohms. Practically, this 4to 1 impedance mismatch not only re-sults in lower signal to the TN' input,but produces all sorts of trick effects,such as ghosts. Folding the dipole

To DIPOLE

2.DNS

TUNER

10- 300 OHMS

STANDARD300 OHMS

INNER STUB140 OHMS

FIG. 2: OPERATING PRINCIPLE ofdipole matching transformer.

changes the impedance to 300 -ohms,but this presents mechanical problemswhich would impair the basic sim-plicity of the design.

This basic matching problem wassolved by utilizing the electricalprinciple illustrated in Fig. 2. Insidethe ordinary 300 -ohm lead are placedtwo additional strands of wire. Thecenter matching stub (two innerwires) is 3532 in. long, and the outerset is 39 in. long. Effectively, the twoouter wires constitute an open wiretransmission line of a quarter -wavelength. This length is cut for thecenter of the TV band.

The two inner wires also constitutea quarter -wave transmission line withan impedance of about 140 ohmssince the two wires are spaced closertogether. Note that one end of theline is shorted. Hence, the two tiedtogether give an impedance of ap-proximately 72 ohms, the nominal im-pedance of the dipole.

Each dipole element for vhf chan-nel 13 is only 27 in., while that forchannel 2 is 48 in. Measurementsshow that elements 27 in. long pro-vide impedance mismatches as high as


FIG. 1: THREE VIEWS OF VI-FI indoor antenna show unit with elements fully extended,with dipoles telescoped and folded into case, and with dust cover closed.


The

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RCA WT -110AAutomatic Electron

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With RCA's exclusive accessory punch and card kit, yourWT -1 10A tester is always up-to-date as fast as new tube typepunching information is announced. When you use the RCAWT -1 10A-the ultra -modern way to test tubes-you gain speedand accuracy for extra service income, and improved efficiencywhich pays for the tester in a very short time!

Remember, when you choose RCA's WT -110A AutomaticElectron -Tube Tester, you also choose a brighter profit picture-now and in the future.

Fully automatic! Sets up all socketconnections and all operating volt-ages for heater, control grid, plate,screen grid, and bias.

Checks for shorts and leakage be-tween each element and all othersconsecutively-plate, screen, controlgrid, cathode. Multiunit tube sectionschecked individually.

Checks amplifier tubes for transcon-ductance-green scale indicates nor-mal range of tube's transconductance.

File capacity for 700 cards.

High- and low -sensitivity ranges forgas and leakage tests.

Automatically selects correct testconditions from 220 different heatervoltages (from 0.1 volt to 120 volts)at currents up to 4 amps., 10 biasvoltage, and 11 values of cathoderesistance.

Rectifier -type tubes tested for emis-sion under heavy load currents (upto 140 ma per plate).

12 -volt plate -and -screen supply fortesting new auto -radio tubes.

See Your Authorized RCA Test Equipment Distributor!

RADIO CORPORATION OF AMERICAElectron Tube Division Harrison, N. J.


TUBE news

Earth's Field Effects

on Color TV Tubest

DUE TO BULB shape, the distancetraveled by an electron is greater forthe edge of the screen than for thecenter. Considering first the verticalcomponent of the field, the deflection,the motion of the apparent source ofelectrons in the deflection plane, andthe misregistration in color -TV tubesbetween beams and dots will ob-viously be larger for the two sides ofthe screen than for the center. At thetop and bottom of the screen, whilethe distance traveled is the same asfor the sides, the vertical field is notnormal to the beam path. The net ef-fects are actually somewhat less at topand bottom than at the screen center.When the center of the screen is puri-fied, there is a misregistration of about.002" at the sides and less than .001"in the opposite direction at top andbottom. If there is also a horizontalcomponent perpendicular to the tubeaxis, as when a tube is aimed east orwest, the pattern is, of course, similarbut rotated. In the frame -type tube,this effect is attenuated sufficiently sothat other effects are more significant.

The field component parallel to thetube axis has a different effect. Allbeams scanned to the edge of thescreen have a radial velocity compo-nent which is perpendicular to thisaxial field component resulting in atangential displacement of as much asthree to four mils, in some locations.This is counter -clockwise when thetube is aimed in a northerly direc-tion, clockwise when it is aimed in asoutherly direction and zero when thetube is aimed east or west. No correc-tion can be designed into the tube,although a steel aperture mask is ofsome help in reducing the effect. Thebest method of compensating for thiseffect is a so-called field neutralizingcoil which is wound around the largeend of the tube and connected to avariable de source. This coil producesan axial field which bucks out the

tPart II of an article based on a talkdelivered at the IRE-EIA Fall Meeting,Toronto, Canada, by G. A. Burdick, TVPicture -Tube Division, Sylvania ElectricProducts, Inc. Part I appeared in March1958 issue of SERVICE.

axial earth's field component-not per-fectly, but adequately.

Up to now, it would appear thatthe steel mask and frame are the an-swer to such a problem, since theyprovide free shielding. Actually, theframe has been termed a ijuxshuntrather than a shield, since action ismore aptly described by this name.While the frame attenuates the field,it also distorts it. It is difficult tomeasure the magnitude and directionof this distorted field, since the fieldis weak and varies rapidly near theframe, necessitating the use of a smallbut sensitive gaussmeter. It is equallydifficult to present a picture of a threedimensional vector field on a slide.Fig. 1, a two dimensional plot, il-

lustrates the major distortion; thedrawing represents a plot of the fieldin the plane of a rectangular frame,the arrows representing magnitudeand direction. Only the component inthis plane is represented on this fig-ure, the axial component being ig-nored. In the vicinity of the frame, thefield is actually reversed in direction,which tends to counteract the effectof the field further back in the coneregion of the tube. The apparentelectron source, therefore, appears tobe closer to the axis for the top andbottom of the tube than for the centerand sides.

The field is, of course, different foreach frameeach orientation of the tube and varia-tion in the earth's field. To determineaccurately a multitude of fields andraytrace electron paths is a practicalimpossibility if not a theoretical one.

Color -TV tubes being made at thepresent time, such as the 21CYP22,normally require a compromise puritymagnet adjustment and may requiresome external aid in the form of ashield, field neutralizing coil, or ad-justable magnets for some of the pos-sible geographical locations andorientations, but may be satisfactorywithout external help in other orienta-tions. Adjustable magnets have theadvantage of flexibility and cost,while the field neutralizing coil hasthe advantage of simplicity of ad-justment.

FIG. 1: TWO DIMENSIONAL PLOT of afield in the rectangular frame of a colortube: arrows represent magnitude and

direction.

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ASSOCIATE INSTITUTE OF

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by PERRY SHENEM AN

HIGH FIDELITY is generally associatedwith complex circuitry and expensivecomponents. A new series of ampli-fiers* provides quality sound re-production with a minimum ofcomponent parts. These high-fidelityamplifiers are used by the manufac-turer in its better -quality televisionreceivers and phonographs.

Basically, the amplifiers consist ofa printed -wiring board and utilizes aphase inverter, audio amplifier andpush-pull output stages. By usingvarious tube types and design con-siderations, four amplifiers have beendeveloped ranging from five to thirty

Hi-Fi Amplifiers For TV Receivers

watts. A typical circuit of this hi-fiamplifier is shown in the schematicdiagram, Fig. 1.

Service of these amplifiers is similarto most amplifiers. In soldering com-ponents on the printed wiring board,apply heat carefully. Excess heatmay cause a break in the bond be-tween the chassis board and the print-ed wiring. If the bond does becomebroken, a jumper wire can be solderedbetween the damaged portions.

When replacing a speaker or add-ing an additional one, all the speakersshould be phased to insure optimumsound reproduction. When in use thecones of all speakers should move inthe same direction at the same time.

To phase a speaker properly, placethe voice coil leads across a 1.5 -voltflashlight battery and note the direc-tion of the cone movement. Findwhich lead, when connected to thepositive terminal of the battery,moves the cone forward. Connect thislead on all speakers to the high sideof the output transformer.

The amplifier may be checked forgain and frequency response by usingan audio oscillator with a flat outputfrom 40 cycles to 40 kilocycles and avacuum tube voltmeter, preferablywith a decibel scale. To performthese checks first disconnect speakersand then connect a 3.2 -ohm 10 -wattresistance across the secondary of theoutput transformer. Connect theground lead of the audio oscillator tothe chassis and the audio oscillatorsignal lead to the audio input socket.Allow a one -minute warm-up period.

To check amplification, adjustaudio oscillator output to 0.7 volts at1000 cycles as measured from theaudio input socket to chassis ground.Measure the output voltage across the3.2 -ohm resistive load.

To check the frequency response,adjust the audio oscillator output to0.7 volts and change the oscillatorfrequency in uniform steps between40 and 14,000 cycles. Readjust oscil-lator output to 0.7 volts each time anew frequency setting is made. Theamplifier output voltage at each stepshould be 5 volts ± 1 db.

*Manufactured by Admiral Corp.

=I. 4)-751

MMFD

3 MEG

1 35

a

100,000%OHMS

MEG

33p000005

111F0owl;

L -.005

MFD

047M D

1/2 I2AX7 i/2112AX7AUDIO AMP PHASE IND

VIA VIM

NW220,000 OHMS

220,000OMMS

022MFD

33MEG

6602 68000.15

047MFD

5Y3GT 100OHMS

044 1=O'0..-'

To To LIll

FD MFD MFD

telt

6A05A0010 OUTPUT

V2

IMO10,000.s I

.0470411.15MFD

470,0006A05

AUDIO IOUTPUT

V3 0

Lrit-coa1

FIG. 1: CIRCUIT DIAGRAM of typical Admiral amplifier which is used in the manufacturer's better -quality TV receivers andphonographs.


a

NOW, "SNOW-WHITE" TUBE MANUFACTURE .... PLUS VITAL DESIGN IMPROVEMENTS!

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YOU CAN SEE WHY the Service -Designed 1J3 out -performs its proto-types! The new spiral -wound filamentshield (right) won't bend from elec-trostatic pull. Filament distortion,and the shorts it causes, are cut 'waydown. The 1J3 takes high peak anodevoltages in stride!

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Customer complaints from rectifier -tube failureswill drop sharply once you install new GeneralElectric Service -Designed 1J3's. These tubes willstand up under the severe peaks common both withhigh line voltages, and where TV sets employ ex-ceptionally high picture -tube voltages.

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Built-in power supply

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Antenna Digest(ContintiPri fMtn page 21)

30 to 1 in the low vhf bands and 7 to1 in the high vhf bands. These mis-matches are apparently due to a largecapacitive reactance. The picture ap-pears with numerous ghosts andsmears.

Cancellation of the large value ofcapacitive reactance is accomplishedby adding an equal inductive reac-tance to each dipole element. Thisbrings the dipole element to resonanceat a particular frequency and therebyprovides a good impedance match. Anadditional problem arising is that ofkeeping the impedance matched fromchannel to channel. Slug tuned coils,mechanically ganged as shown in Fig.3, provided the answer.

Two ferrite rods are held togetherby a plastic rod made of Cycolactl,which does not affect tuning. Notethat the tuning tab is not centered onthe rod. This is done in order to havethe ferrite in the coil on the left justenter the coil at the B end while theferrite on the right is just entering itscoil at the C end. Each dipole ele-ment is thus balanced and its length isadjusted electrically.

Advantages of Slug Tuning

This method of slug tuning elimi-nates one of the major problems of in-door antennas. When a dipole elementlength is adjusted by hand a bodycapacitance is added to the antenna.A properly adjusted picture obtainedin this fashion may fade away or dis-tort in one form or another whenthe hand is removed from the dipoleelement. The slide tuner on the Vi-Fiantenna tends to overcome this defect.

Experimental impedance values ofthe antenna were measured, with thetuner and the matching transformerinstalled. The mismatch across thehigh vhf band had dropped as low as3 to 1 while the low band vhf valuesdropped as low as 1.5 to 1. The corn -

Registered trademark, MarbonChemical Div. of Borg-Warner Corp.

FIG. 3: ARRANGEMENT OF SLUG -TUNED Coils in Vi-Fi indoor antenna.


DIPOLES-

II

I I I

L_

IISLIDERULE

TUNER

iEQUIVALENTI MATCHING;TRANSFORMER

FIG. 4: SCHEMATIC DIAGRAM of Am -phenol Vi-Fi Indoor Antenna.

plete schematic for the antenna ap-pears in Fig. 4.

The vhf dipoles were collapsed totheir shortest length, and the im-pedance was measured in the uhfband. Plotted values netted a mis-match which ran as high as 20 to 1.This was attributed to the fixed in-ductance in each leg of the dipole.Since this inductance could not beswitched or tuned out, without affect-ing the performance of the vhf anten-na, a separate folded dipole was de-signed, mounted under the bottomcover, and a standard length of 300 -ohm twin lead was used for connec-tion to the set. Experimental measure-ments were then taken and the mis-match had dropped to an average of3 to 1 over the entire uhf band.

1 he antenna was field tested inseveral metropolitan areas with satis-factory results.

HEAVY-DUTY TV TOWER

COMMUNICATION AND HEAVY-DUTY TVtower featuring 12) in. equilateral tri-angular design, 13a in. extra -heavy -gaugetubing for side rails and zig-zag solid -steel cross bracing. Said to be self-sup-porting up to 50 ft. heights or guyed upto 150 ft. Available in hot -dipped gal-vanzed or enamel finish. (No. 25; RohnManufacturing Co., 116 Limestone,Bellevue, Peoria, Ill.)

1hl'

AmperexECC Series

...a quiet revolutionin miniature twin triodes

IMPROVED PLUG-IN REPLACEMENTS for the 12AT7, 12AU7 and 12AX7

Have you noticed, in the tube line-ups of the latest and finest audio and radioequipment, that the designations "12AT7," "12AU7" and "12AX7" are graduallydisappearing and are being replaced by "ECC81/12AT7," "ECC82/12AU7" and"ECC83/12AX7" instead? This has been happening quietly, without much fan-fare, because the Amperex ECC series twin triodes are not very different fromtheir conventional equivalents. Not very -but different enough, improved enough,to be inevitably and invariably preferred by those who know and care. Thedifference is in the internal tube structure, as seen in the illustration below,

and in the special manufacturing techniques developed for this series by Philipsof the Netherlands, world pioneers in audio tube research. In every way, it isgood engineering sense to plug an Amperex ECC81, ECC82 or ECC83 into anysocket that accepts a 12AT7, 12AU7 or 12AX7- because the ECC's are bettertubes and (most important of all) they cost no more!

0 Electrode structurecompletely rigid andimmobile-for greatlyreduced tube noiseand microphonics.n Tungsten filament is

Y-7 double helical-forsignificant hum reduc-tion through magneticcancellation.

e% Filament structureVor has no sharp bends-

for prevention of thetype of burn -out thatshortens life of con-ventional folded type.

s.

V.

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ILWRIL11311111101///,-,Fr,

OTHER AMPEREX TUBESFOR HIGH-FIDELITY AUDIO APPLICATIONS:

EL84/6BQ5: 9 -pin power pentode; 17 W PP6CA7/EL34: High -power pentode; 100 W PP

EF86/6267: Low -noise high -u pentodeECC85/6AQ8: High -u dual triode for RFGZ34/5AR4: Cathode -type rectifier; 250 ma.EZ80/6V4: 9 -pin rectifier; cathode; 90 ma.EZ81/6CA4: 9 -pin rectifier; cathode; 150 ma.

At All Leading Electronic Parts Distributors

ask Amperexabout special purpose tubesfor radio and TV

Detailed data, as well as applications engineering assistance to manufacturers and pro-fessional designers, available from Semiconductor and Special Purpose Tube Division,Amperex Electronic Corp., 230 Duffy Avenue, Hicksville, Long Island, N. Y.


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"It's a JENSEN NEEDLE"

Signal Distribution Pattern of Ultrahigh

Parabolic Antenna System

A \ t \ IBLII OF READLIIS have expressedinterest in the uhf parabolic antennadescribed in a recent report' and haverequested further clarification of theantenna distribution patterns dis-cussed and illustrated in this article.The authors pointed out that all an-tennas have a natural tendency to de-velop a narrower beam as frequencyincreases. Most of the time this is adesirable feature. However with para-bolic antenna, too narrow a beam inthe dipole system would be a disad-vantage since it would prevent thedipole from picking up reflected signalfrom the outer edges of the screen.A major objective in the design of thisantenna, therefore, was to maintaina uniform beam width over all uhfchannels.

Fig. 1 shows the antenna and threepatterns produced by it. For the sakeof clarity, the diagram shows the an-tenna acting as a transmitter ratherthan as a receiver. This is permissiblesince the theory of reciprocity statesthat the patterns of an antenna areidentical regardless of whether the an-tenna is used to receive or transmitthe signal.

Fig. la shows the ultrahigh para-bolic antenna' discussed in the article

'Ultrahigh Parabolic Antenna SystemDesign and Installation, Harold Harrisand Paul Mattern, SERVICE, APRIL,1958.

'Para - Scope antenna produced byChannel Master Corp.

in its normal operating position. Theideal distribution pattern, which thedesigners of this antenna strove to ob-tain at all frequencies, is illustrated inFig. lb, where the beam is wideenough to illuminate the entire surfaceof the screen. With higher frequencies,however, the dipole asserts its naturaltendency toward a narrower beam,producing the pattern shown in Fig.lc. Only the inner part of the screenis illuminated by this signal, with aresultant decrease in gain. This ten-dency is overcome by varying the de-sign of the feed system.

Overcorrecting the feed system willproduce too wide a pattern as shownin Fig. ld. This pattern is also ineffi-cient because a portion of the signalescapes beyond the outer edges of thescreen and is not utilized. A properlydesigned antenna will hold the beamwidth constant so that the entirescreen is illuminated over the fullrange of the ultrahigh frequencies.

Although the horizontal pattern isnormally of more concern to the Ser-vice Man, the vertical pattern is ofequal importance in an antennaof this type. The feed systemreceives its signal from a round screen,as illustrated in Fig. la. Thereforeboth horizontal and vertical beamwidths must be matched as closelyas possible so that the dipole can re-ceive signals with equal efficiencyfrom all points on the round screen.

'

a

\"IC..'1',....,-...,

-......_

(---"

.

C> C '''''

-0 __11-)

FIG. la: PARABOLIC ANTENNA in normal operating position. Fig. lb: Ideal distribu-tion pattern produced by this type of antenna. Fig. lc: Signal distribution pattern witha narrow beam which is not properly corrected. Fig. ld: Pattern resulting from anovercorrected beam which is two wide to be fully reflected by the screen. The patterns

shown in both Figs. Sc and ld result in decreased gain.


Power Supply(Continued from page 16)

8 amps at 16 v on the 0-16 v range, asudden reduction in the current from8 to 4 amps will cause the outputvoltage to rise to 18.8 v. In this waythe performance of this unit may benoted at all varying loads.

The floating output terminals makeit easy to supply the required polarityto the circuits under test. All transis-tor car radios as well as transistorportables can be checked over therange of supply voltage variations thatmay be anticipated. This power sup-ply also facilitates servicing of hybrid -type automobile receivers, since hy-brid tubes are especially susceptibleto ripple in the voltage supply.

O

JJ

aJhi

10

2

0

2,,

,iWO

x

(36

0 C VOLTAGEOUTPUT -VOLTS

0-16 VOLT P05111061

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SETTINGVARIASLE

LOADONUS 6.610 20 lins, -111...-"mumw.0.....MMIS

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0 0 'IP R.2 OHMS

0 2 3 4 6 6 7

DC OUTPUT CURRENT -AMPS

FIG. 3: PERFORMANCE CHARACTER-ISTICS of type EFB power supply in the

0 to 16 volt range.

0

S

O

10

4

2

0

ii_. D C VOLTAGEOUTPUT - VOLTS

aa 6210-32 VOLT P06ITION1

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446.60 OHMS

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GETTING

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FIG. 4: PERFORMANCE CURVES of DCpower supply unit in the 0 to 32 volt

position,

Servicing is fasterwith SONOTONE

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Because50 manufacturersuse them in 417phonograph models

No wonder you can finish replace-ment jobs faster. Sonotone is thestandard cartridge of the phono-graph industry - no more customfitting or time -wasting adjustment.Sonotone fits over 90% of all yourquality calls-means less inventoryto stock and check, too.

But that's only half the story.When you put in a Sonotone, yougive your customers great sound.Flat response from 20 to 20,000 cps,whether they have pre -amp andequalizer or not! Either way, youcan't miss with a Sonotone.

Order Sonotone Ceramics fromyour dealer now. For full infor-mation, including replacementcharts, write:

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ELMSFORD, NEW YORK

O

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LAYER -BUILT COLOR -GUIDE

Before you build another kit see this newmethod of Kit Assembly. Each kit is com-plete with all parts and the new exclusive"Little Genie" Instruction Book.

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207A -K Hi-Fi Preamplifier. The Ideal control unitwith self -power feature for use with any basicamplifier. True flexibility with 10 separate con-trols. Feedback throughout for low distortionand wide frequency response. In charcoal grayand brass. Shpg. Wt. 10 lbs.Complete Kit and instructions Net 44.50

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OX F OR 1]SPEAKERS

You obtain the finest sound reproduction when youselect the proper speaker for the specific application.Each OXFORD SPEAKER is "tailor -designed" to actually"fit the need."

Specify OXFORD when you next require quality speak-ers. Remember: Oxford quality has consistently beensuperior for over thirty years.

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Repairing Printed -Wiring Board Chassis*

by L E R O Y WOLFF, Field Service Engineer, Motorola, Inc.

IN REPAIRING p -w boards, the solderpot should not be used to solder theparts into the new board; this can bedone much more efficiently with asoldering iron. Be sure the iron tip isclean and well -tinned. Apply the tipof the iron to the lead or lug, installedin its mounting eyelet on the board,long enough to heat it sufficiently toflow solder. Use 60/40 resin -coresolder. The solder should be appliedto the lead or lug long enough toallow solder to flow down it, themounting hole filled and a little pro-trusion formed on the other side ofthe board; then the iron should be re-moved immediately. A joint made inthis way will never cause trouble, noris there any danger of damaging theboard. A little intelligent practice willsoon provide the facility of operationneeded to make a good connectionevery time, and to do it swiftly with-out damage to the board. One should

aiR

bear in mind that the mass of thelead or lug will be a factor in thelength of time the iron must be ap-plied, and this can only be judged byobservation and experience.

The board should be supportedadequately while assezni: - andsoldering it.

Replacement of Individual Parts

Standard Two -Lead Resistors andCapacitors: Sometimes, where posi-tive indication that a resistor orcapacitor is defective exists, it may bepossible to replace the defective unitwithout removing the chassis fromthe cabinet. If the leads of the defec-tive unit are long enough, they shouldbe clipped as close as possible to the

°Third and final part of a series onthis subject. For earlier articles, seeSERVICE, Jan. 1958 and Feb. 1958.

MAKE SURE IT FITS!

171°

4

Our newcatalog isavailable . . .

write for yoursNOW!

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gooide

for makingservice callsmore profitable9 out of 10phonographs

need new

needles

On your next service call, ask yourcustomer if you can check his phono-graph needle. Chances are nine outof ten that it's worn to the point ofdamaging records. With a stock ofFidelitone Needles in your servicekit, you've made a profitable sale.

A Fidelitone Diamond is thebest replacement buyA Fidelitone Diamond gives yourcustomers the maximum number ofsafe playing hours. This high qualityneedle is scientifically produced tocartridge manufacturers' specifica-tions; always precision mounted forperfect alignment and orientation.

Be ready to make the saleIt's far easier to make the sale if youhave the right needle with you. Eventhough there are hundreds of needletypes made, you can replace themajority by carrying a minimum ofFidelitone needles. Carry a repre-sentative stock of Fidelitone withyou and include the fast selling Dia-monds for more profit on servicecalls. Call your Fidelitone Distributortoday.

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unit, and these leads should be usedto connect and solder the replacementunit.

Res -Cap Assemblies

Multi -element assemblies of re-sistors and capacitors as used byMotorola are designated as res-caps.Usually, if one component in such anassembly fails, the lead or leads con-necting the unit to the board can beclipped loose and an individual com-ponent of the same value can beconnected in its place, avoiding thenecessity of replacing the entire unit.This is permissible, but care mustbe used in tracing connections to besure that, because of an internal con-nection in the res-cap itself, someother component will not be left float-ing. For instance, in an intertubecoupling assembly, the connectionsfrom the res-cap to the grid of thesecond tube may be connected insidethe res-cap to one side of the inter -stage coupling capacitor and to thegrid resistor of this tube. If the coup-ling capacitor shorts or becomes leakyand has to be replaced, it can be doneby clipping the res-cap lead at thegrid and also the lead from the coup-ling capacitor to the plate of thepreceding tube and then using an in-dividual unit of the same value. But,since clipping the original grid leadalso removes the connection to thegrid resistor, a separate grid resistormust also be installed; otherwise thegrid would be left floating, whichcould lead to some unusual symp-toms.

Excessive Heat Harmful

Res -cap connections are vulnerableto damage if excessive heat is allowedto travel up the leads and to theirjunction with the various componentswhich have a Durez coating. Careshould be exercised to protect themfrom this type of damage by goodsoldering technique.

Complete removal of res-caps,such as would be necessary in a trans-fer of components from a brokenboard, should always be made withthe use of a soldering pot.

Multi -Lug Components

A soldering pot should be used forthe removal of sockets transformers,electrolytics, gangs, etc. As previouslymentioned, such items can be removedwith an iron, but the operation is veryslow and can easily result in damageto the board or component,

"OUTPERFORMS THEM ALL"I. J. Saltzman, GlobeSound Service,Jamaica, N. Y., experi-enced commercialsound engineer, says:"On side by side com-parison test, the CJ -44outperforms them all."

ATLAS "King Cobra-Jector"

CJ -44

I[Shownwith

IGB-1UniversolMounting

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Complete with"Acousti-Match"

Built-in Driver Unit

List $72.50

NET $43.50

A wide-angle, all-purpose, all-weatherPublic Address Speaker, complete withintegral high -power super -efficient"Acousti-Matched" driver unit."Acoustic -Matched" means "ControlledResponse" within the frequency limitsmost useful in P. A. and high level musicreproduction. "Controlled Response"offers conversion efficiency never beforeobtainable in high-powered speakers."Controlled Response" results in smoothreproduction - free from peaks which sooften create and sustain acoustic feed-back.

The CJ -44 conserves costly amplifier outputpower - fewer speakers do a completejob. The speaker horn is easily rotatedfor horizontal or vertical dispersion

patterns.The CJ -44 is the only high-powered P. A.speaker that can be equipped with thenew Atlas Universal Mounting Bracket,permitting quick and secure directionaladjustment on both planes. Simple tomake a horizontal or vertical adjustmentas a final "touch-up" to the installation.The CJ -44 is designed for the "tough jobs."No gimmicks, no fluffs, no wild claims- just a reliable super -efficient speakerfor all applications.

Input Power: 30 watts constant50 watts peak

Input Impedance: 16 ohmsResponse: 150-9,000 cps

Dimensions; Bell 23" x 13";Over-all length 19"

Net Weight: 16 lbs.Write jot free Catalog 58.

ATLASSOUND CORP.1442-39 St., Brooklyn 18, N. Y.

Atlas Radio Ltd Toronto, Canada


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Miniaturized

Circuitry Analysis of

by FRED J. KITTYGeneral Instrument Corporarton

THE UHF TV BAND was opened tocommercial use late in 1952. Thisband, extending from 470 to 890 mc,afforded 70 additional channels (14through 83) to provide properly forthe anticipated growth of telecasting.

Since its inception, however, uhfhas been in a difficult competitiveposition vis-a-vis vhf. One reason forthis was the entrenched position ofvhf at the time uhf was introduced.In addition, uhf also suffered in atechnical comparison with vhf be-cause of the higher frequencies in-volved.

The performance of a uhf receiveris established by the uhf tuner. Dueto the technical advantages favoringvhf, the history of uhf -tuner develop-ment has been basically a continuingstruggle to improve performance par-ticularly as regards noise factor. Asa result of this effort, uhf receivernoise figures have improved by ap-proximately 10 db in the last fiveyears as compared to an improvementof perhaps 1 or 2 db in vhf receivers.

The key questions to be answeredin the early days were: "Can you seea picture? How far is the station?"As noise figures improved, require-ments were added involving suchparameters as if, image and unbal-anced signal rejection as well asantenna match. Somewhat later, max-imum oscillator radiation limits wereset by FCC. With the advent of color,oscillator drift and stricter passbandspecifications entered the picture.

While these technical requirementswere being added, TV set prices werecontinuously being reduced. Conse-quently, TV set components, includ-ing both vhf and uhf tuners werebeing reduced in price and size. Thus,technical and economic factors dic-tated that the design of modern uhftuners be quite sophisticated. In thisregard, it might be noted that me-chanical design was a major engineer-ing element since the evolving TVset required a small, but sturdy, andutilitarian package.

As the state of the art advanced, itbecame clear that the most efficient


Compensation -Type UHF Tuner

Ultrahigh Development With Radiation -Suppression Features

uhf receiving system, consideringeconomic and technical factors, aswell as FCC regulations, would be asingle superheterodyne using a6AF4A (or equivalent) as the oscil-lator and a crystal diode (IN82A orequivalent) mixer -converter, and anif frequency of 41.25 mc (sound)with no rf amplification ahead of themixer.

Practically all present day uhftuners are built along these lines.Furthermore, a variable capacitorassembly has evolved as the mostcommon timing method. Thus, assum-ing the basic merit of the circuitspreviously chosen, it is seen that thedesign of modern uhf tuners hasbecome a matter of circuit and struc-tural refinement.

Of the several areas of operationopen to the designer, the one afford-ing the most profit is that involvingthe design of the preselector andoscillator coaxial lines, which withvariable capacitors, are the basictuning elements. Two preselectorsare provided to afford sufficient skirtselectivity. A single preselector wouldprovide lower insertion loss and con-sequently a better noise factor, butimage rejection specifications of 40-dbminimum require two preselectors atthe band -widths and if frequencies in-volved. Further, and regardless of theimage specifications, two preselectorsare required to insure adequate block-ing of the local oscillator frequency;i.e., 43.5 mc above the signal fre-quency. Otherwise excessive oscillatorenergy will appear at the tuner an-tenna terminal and consequently theradiation will be above FCC limits.The loaded Q of the preselector cir-cuit is governed by skirt selectivity;i. e., image rejection and oscillatorradiation requirements. Since the in-sertion loss of a preselector varies in-versely as the unloaded -to -loaded Qratio, it is evident that a high un-loaded Q is desirable. Loaded Q's inuhf tuner preselectors run in the orderof 25-50. To keep the insertion lossbelow X db per preselector requiresan unloaded -to -loaded Q ratio of 20.This, in turn, sets the requirement forunloaded Q's in the 500-1000 range.The unloaded Q depends upon theimpedance of the line (which in turn

is a function of the dimensional rela-tionship between inner and outer con:-ductors) and the length of the line.

An additional requirement on thepreselector lines is the ability to tuneover the 470-890 mc range with a

No. 5 of a series

reasonably sized set of capacitorplates. The amount of tuning ca-pacity required is also a function ofthe impedance and length of the line.Prior to the development of the model


of questions for progressive technicians.

Can You Handle This Problem?R -F AMPLIFIER

How'd you do on this one? Was iteasy . . . middling hard . . . or tough?

It was easy or tough depending onhow well you know your electronicsfundamentals.

That's the way it is on the job too.Day after day we get the same kindof reports from ambitious men likeyourself in the field. "I was interestedin these problems . . . your traininggave me the principles . . . I solvedthe problems . . . I got a better job. . . and now I make more money."

What WillRF Meter

1a A1 Read?(Answer printed below/

1. Zero, or nearly so.2. A little less than 3 ma.3. 3 ma.4. A little more than 3 ma.5. Many times more than

3 ma.

Why put a ceiling on your income . . .

and on the satisfaction you can getout of doing the more challengingjobs. Get your fundamentals moresolidly-then take off and really go!

The answer to our little problem isgiven below. If you want a completesolution, just fill out and mail thecoupon.

low Aie+Pw!-X0Jdth ew £ uey. GJOW SOUJR Au pH g

Cleveland Institute of Radio Electronics4900 Euclid Avenue, Dept. S-12, Cleveland 3, Ohio- - - - - - - - - - - - - -

Please send me detailed solution to problem above andinformation on how I may prepare for the increasingopportunities in electronics. There is no obligation.

S u e

EiF-ctrohicsTraining -

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Installing Motel Master Antennasby TOM SHEA

Sales Engineer, Blonder -Tongue Laboratories

MANY MOTELS are now installing cen-tral antenna systems in place of indi-vidual antennas for each TV set. Adiscussion of the advantages of amaster antenna installation and a de-scription of a system suitable for usein 90 percent of existing motels ap-peared in a previous report.'

Before considering the installationand servicing of master antenna sys-tems, the basic design principles mustfirst be established. For this purpose,we may consider the typical installa-tion described previously' which isillustrated in Fig. 1. A proper under-standing of design considerations willbe extremely useful in troubleshootingand servicing the system.

The basic design principle may be

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SPECIFICATIONS

MAX. AC INPUT VOLTAGE40K130

MAX. PEAK INVERSE VOLTAGE 400

MAX. PEAK CURRENT (MA) 7500MAX. DC CURRENT (MA) 750

arkesTarzian.,

DEPT. S-3,

K-200130 APPROX. RECTIFIER VOLTAGE DROP

40K

2

K-2002

360 MAX. OPERATING TEMP. 100 C 100 C

2000 MAX. SURGE CURRENT (AMPS) 30 20

200 MIN. SURGE LIMITING RESIS. (OHMS) 7.5 10

DIMENSIONSCERMIIC HOUSING

An" DIABARE TINNEDCOPPER HIRE

PLASTIC

RECTIFIER DIVISION, 415 N. COLLEGE AVE.

BLOOMINGTON, INDIANA

IN CANADA: 700 WESTON RD, TORON1O 9, TEL. ROGERS 2.7575 EXPORT: AD AURIEMA, INC., NEW YORK CITY

summed up briefly. First, satisfactorypicture must be obtained on all de-sired channels with a standard broad-band antenna feeding a standard TVreceiver. Then, if the gain at the headend is equal to or greater than the cal-culated loss in the distribution section,satisfactory reception will be assuredat all outlets.

There are four basic steps to befollowed in the design of a motelmaster antenna system. First is thelayout of the main cable run. Next thetype of tapoffs to be used must be de-termined. The next step is to calcu-late the distribution system loss.Finally an amplifier must be selectedwhich will overcome this loss.

Blueprints or a drawing of the motelwill be helpful in determining the lay-out of the main cable run. As in themotel design shown in Fig. 1, horizon-tal cable runs are most economical forlong, low structures. These are bestlocated in an attic or a crawl space.RG 11/U coax should be used, andthe run should be split into the num-ber of branches that permit the short-est possible cable runs.

The type of tapoff used will dependupon the physical requirements to bemet within the structure. For newconstruction, a flush - mounted singlewall outlet is generally preferred. Asingle -outlet tapoff suitable for out-door system installation is used wherean indoor run system is not feasible,and an indoor two -outlet tapoff maybe utilized where an attic or crawlspace main cable run is possible. Themotel system shown in Fig. 1 utilizestwo -outlet indoor tapoff as conditionswill allow for them. This installation,which provides two outlets with eachtapoff, cuts installation time and laborcosts in half.

Calculating Losses

The total system loss is calculatedfrom the last TV set on the longestbranch line to the head end. This willdetermine how much gain will be re-quired in the amplifier to be used.The unit for measuring signal gain orloss used in system calculations is thedb. The db is used for practicalreasons because it allows for simpleaddition or subtraction in arriving atthe resultant loss or gain of signalstrength.

The four losses that must be takeninto account are the main cable loss,

'Installing Master TV Antenna Systemin Motels, Tom Shea, SERVICE; April,1958.

0


FIG. 1: TYPICAL MASTER antenna sys-tem suitable for use in 90% of existing

motels.

the tapoff isolation loss, the tapoff in-sertion loss and the splitter loss. In amain cable consisting of 300 feet ofRG-11 U coax, such as is used in theinstallation previously described andillustrated in Fig. 1, the loss is ap-proximately 9 db. The tapoff isolationloss was previously' given at 17 dband the tapoff insertion loss at 0.5 dbfor each tapoff in the branch lin('being considered. With 15 tapoffs ineach branch, the total tapoff insertionloss may be regarded as 7.5 db.Finally the two-way line splitter' de-scribed in this installation provides aloss of 3 db. Adding up the losses,wo, arrive at a total distribution lossof 36.5 db for the entire system.

With a system loss of 36.5 db toovercome, an amplifier with at leastthat much gain must be used. It isalso desirable to use a broadband am-plifier which will amplify all VHFchannels. The broadband amplifier'described in this installation has again of 37 db. After subtracting the36.5 db system loss, the net gain inthe last TV set in each branch is 0.5db over the original antenna signalstrength. If fewer than 15 tapoffs areused in each branch or the length ofthe cable is less than 300 feet, theresultant signal gain at the last TVset will be increased.

Testing Installations

The master antenna installation de-scribed here may be checked forproper signal strength and directionat various test points designated inFig. 1. The required test set-up isshown in Fig. 2 and requires an at-tenuator, a matching transformer, anda portable TV set. The attenuatorpad provides a 0 to 45 db range of,attenuation in 3 db steps. The basicrequirment at all test points is thatsnow -free and interference -free re -


'Blonder -Tongue MDC-2.°Blonder -Tongue type MLA.

AT TENUATOR PADO to 460 in 30 Steps

730- Ce0 inita 11659/11Cea

PAD VALUES 3db 6db 12d3 24do

50 1600 Unit

PORTABLET VSET

FIG. 2: TEST SET-UP and connectionsrequired for checking installation ofmaster antenna system from various test

points.

RG 300 OHMATTIC TWIN LEAD

BROAD BAND ANTENNA

RG II/u MAIN CABLE

TAPOFF

0 TYPICAL

oo

RISERS 0411V

RGII/u-7

II/u

TV!171±ii 300 OHMRG II/u SET TWIN LEAD

300 OHM TWIN LEAD'TO WALL OUTLET

TELEPHONEWALL PLATE

Compare just released Model 77 to ANY peak -to -peak

V. T. V. M. made by ANY manufacturer at ANY price !

Superior's New Model 77

VACUUM TUBE VOLTMETERWITH NEW 6"

AS A DC VOLTMETER: The Model 77 is indis-pensable in Hi -Pi Amplifier servicing and a mustfor Black and White and color TV Receiver servic-ing where circuit loading cannot be tolerated.

AS AN AC VOLTMETER: Measures RMS values ifsine wave, and peak -to -peak value if complex wave.Pedestal voltages that determine the "black" levelin TV receivers are easily read.

AS AN ELECTRONIC OHMMETER: Because of itswide range of measurement leaky capacitors showup glaringly. Because of its sensitivity and lowloading, intermittents are easily found, isolatedand repaired.

FULL -VIEW METERModel 77 completely wired and calibrated withaccessories (including probe, test leads andportable carrying case) sells for only $42.50.

ro. Model 77 employs a sensitive six inch meter.Extra large meter scale enables us to print allcalibrations in large easy -to -read type.

p Model 77 uses new improved SICO printedcircuitry.

{.0 Model 77 employs a 12AU7 as D.C. amplifierand two 9006's as peak -to -peak voltage recti-fiers to assure maximum stability.

1. Model 77 uses a selenium -rectified power sup-ply resulting in less heat and thus reducingpossibility of damage or value changes of deli-cate components.

Model 77 meter is virtually burn -out proof.The sensitive 400 microampere meter is isolatedfrom the measuring circuit by a balanced push-pull amplifier.

0, Model 77 uses selected 1% zero temperaturecoefficient resistors as multipliers. This assuresunchanging accurate readings on all ranges.

SPECIFICATIONSDC VOLTS -0 to 3/15/75/150/300/750/1,500

volts at 11 megohms input resistance. ACVOLTS (EMS) -0 to 3/15/75/150/300/750/1,500 volts. AC VOLTS (Peak to Peak) -0 to8/40/200/400/800/2,000 volts. ELECTRONICOHMMETER -0 to' 1,000 ohms/10,000 ohms/100,000 ohms/1 megohm/10 megohms/100megohms/1,000 megohms. DECIBELS -10db to -I- 18 db, -I- 10 db to + 38 db, -4- 30 db to-k 58 db. All based on 0 db = .006 watts (6 mw)into a 500 ohm line (1.73v). ZERO CENTERMETER - For discriminator alig_nment with fullscale range of 0 to 1.5/7.5/37.5/75/150/375/750volts at 11 megohms input resistance.

Model 77 comes complete with operating instructions, probe and test leads. Use it on $4250the bench - use it on calls. A streamlined carrying case, included at no extra charge,accommodates the tester, instruction book, probe and leads. Operates on 110-120 volt60 cycle. Only NET

SHIPPED ON APPROVALNO MONEY WITH ORDER NO C 0. D.Try it for 10 days before youbuy. If completely satisfied send$12.50 and pay balance at rateof $6.00 per month for 5 months.- No Interest or FinanceChargerArded.7T not com-pletely satisfied, return to us.no explanation necessary.

MOSS ELECTRONIC DISTRIBUTING CO., INC.Dept. D-473, 3849 Tenth Ave., New York 34, N. Y.Please rush one Model 77. I agree to pay $12.50 within 10 days afterreceipt and $6.00 per month thereafter. Otherwise I may return,cancelling all further obligation.

NAMEADDRESS

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'

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Miniaturized UHF Tuner(Continued front page 33 )

described° requirements were achievedthrough the use of lines 3" long. Inthis model the lines are 2 7/16" long,allowing a reduction in tuner lengthfrom 3%." to 2%", an' important con-sideration in the small, shallow TVsets of the present era. The key tothis size compression was in thechoice of the proper compromise incoax -line dimmensions resulting in aline impedance close enough to affordalmost optimum Q and at the sametime allowing for reasonable tuningcapacity.

With the proper selection of crosssection dimensions to afford proper Qand tunability, the remainder of thepreselector design is that of settingthe loadings at antenna and mixertogether with the coupling betweenthe two circuits. These parametersare adjusted to give a bandpassslightly overcoupled at the extremesof the range and critically coupled atmid -band. Loadings are determinedby the shapes and locations of theantenna and mixer coupling loops inthe coaxial lines.

The design of the oscillator is gov-erned by three basic requirements:(1) Provide sufficient output to drive

the mixer crystal at an efficientoperating point.

(2) Keep power output level lowenough to avoid excessive radia-tion.

(3) Keep thermal drift low.(4) Provide essentially linear fre-

quency calibration.

The basic circuitry used in theoscillator is a grounded plate, tuned -grid modified Colpitts.

It is to be noted that the first tworequirements above are in contradic-tion and compromises have to bemade. In general, too, at uhf peculiarresonances and nodal points are en-countered with resultant oscillatorweak or dead spots. It is importantto eliminate these in order that theoscillator drive be not excessive atsome frequencies in compensatingfor the low activity points. In thistuner these dips have been elimi-nated, as shown by proper oscillatoractivity over the entire band -withB+ voltages as low as 40 v at theoscillator plate.

The main advantage derived fromoperation at low plate voltages is a

°G. I.-F. W. Sickles model 204.



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model description list

AC40Joins 2 sets to 1 antenna $3.50AC6O Joins 3 sets to 1 antenna 4.00AC70 Joins 4 sets to 1 antenna 4.85



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design affording radiation within FCClimits. In the past this has beenachieved only with the costlier plate -tuned grid type of oscillator wherethe ground currents are lower than inthe tuned grid -grounded plate design.To achieve such relatively uniformactivity each possible absorbing ele-ment had to be carefully trackeddown and eliminated, detuned or de -coupled.

Drift Compensating Capacitors

A more difficult problem was thatof making provision in the design forthe addition of drift compensatingcapacitors. Addition of capacitylowers the maximum frequency ob-tainable with a given impedance.Modifying the impedance to allowmore capacity results in decreasedoscillator efficiency. Thus a propercompromise must be arrived at. Anadditional handicap here is that insmall size tuners there is a greateramount of minimum capacity (due togeometry) than is the case for largersized tuners. Heretofore, full com-pensation had been achieved only inlarger tuners. The importance ofproper compensation is vastly multi-plied for color -TV, since a relativelyslight change in frequency will causeloss of color in the picture. With thecompensation provided there is nowa maximum drift in the order of 200-300 kc. This should be compared todrifts upwards of M mc in uncom-pensated tuners.

PICTURE TUBE BRIGHTENER

A PICTURE -TUBE brightener, SP 110, foruse with RCA -type 140° tubes, has beenintroduced by Anchor Products Co., 2712W. Montrose Ave., Chicago 18, Ill.

Adjustment is said to adapt unit foreither series or parallel -wired filaments.Can be used on electrostatic or electro-magnetic -focus tubes. [SERVICE]

the specs are the proof ...the BEST BUYS areL7E/C0for COLOR & Monochrome TV servicing

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cps) ; pre-set TV V & H positions; auto. sync.ampl. & lim. PLUS: direct or cap. coupling;bal. or unbal. inputs; edge -lit engraved incitegraph screen; dimmer; filter; bezel fits stdphoto equipt. High intensity trace CRT. 0.06 usecrise time. Push-pull hor. ampl., flat to 400 kc,sens. 0.6 rms my/in. Built-in volt. calib. Z-axismod. Sawtooth & 60 cps outputs. Astig. control.Retrace blanking. Phasing control.

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SPEED, ease, unexcelled accuracy & thorough-ness. Tests all receiving tubes land picturecubes with adapter). Composite indication of Gm,Gp & peak emission. Simultaneous sel. of any 1of 4 combinations of 3 plate voltages, 3 screenvoltages, 3 ranges of continuously variable gridvoltage (with 5% accurate pot). New series -string voltages: for 600, 450, 300 ma types.Sensitive 200 ua meter. 5 ranges meter sensi-tivity (1% shunts & pot). 10 SIX -positionlever switches: free -point connection of eachtube pin. 10 pushbuttons: rapid insert of anytube element in leakage test circuit & speedysel. of individual sections of multi -section tubesin merit tests. Direct -reading of inter -elementleakage in ohms. New gear -driven rollchart.Checks n -p -n & p -n -p transistors: separatemeter readings of collector leakage current &Beta using internal dc power supply.CRA Adapter 54.50

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SPECIFICATIONSYARIABLI

Input: 115 Volts 50/60 cycles

Output Voltage0-15 Volts and

0-30 Volts

Output Current:MAand 0.60 MA

on both voltage and current

Accuracy: 2 °/.microvolts ( .002°4

Ripple:Less than 500

at full output)

Regulation:1.2 Volts

Maximum; Zero to

full load current

Internal Impedance:Less than 20 ohms

DC to Radio Frequencies(including 7.0

ohm Meter Fuse, optionally removable)

Terminals:5 -Way Binding

Post

Size: 10" x 61/2" x 53/4"Weight: 16 pounds

TRANSISTORPOWER SUPPLY

MODEL A-400Especially designed to operate, service

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Highest quality components combined with

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1051nri2cuteetey Vtaiice 7ootaPREFERRED BY THE EXPERTS

Motel Antennas(Continued from page 35)

ception be obtained on all desiredchannels.

Test point A, directly off the an-tenna, is taken with the attenuatorand set - matching transformer by-passed, producing no attenuation.Test point B, the input to the ampli-fier, is also taken without attenuation.Before checking test point C, the out-put of the amplifier, connect the at-tenuator so that 36 db of attenuationis provided. Test point D checks theend of each branch before the tapoffsare installed and requires 24 db at-tenuation. The last test point E, ateach TV outlet, requires no attenua-tion and consequently is made withthe attenuator and set matching unitby-passed.

Picture Troubles

Any sudden marked change in re-ception is a sure indication of trouble.The type of picture trouble oftengives a good hint as to what may bewrong with the system. A weak snowypicture indicates insufficient signal,weak amplifier tubes, open or poorlymade connections, defective transmis-sion lines. To correct a weak signal,increase the amplification.

Multiple ghosts or smear is often asign of an open or short circuit intransmission line or of improper lineor equipment termination. "Wind-shield wiper," "herringbone pattern,"complete picture breakup, or "ridethrough" of one channel into severalothers are usually caused by an over-loaded amplifier or unbalanced signalsin the line. To correct overloading ofthe amplifier, reduce amplifier gain.

Diagonal lines in pix, light herring-bone pattern, Venetian blind, swirl-ing patterns, or complete pix blackoutmay be the result of RF interferencefrom FM stations, other radio service,TV -set local oscillator radiation, lineamplifier oscillation, co -channel oradjacent channel interference fromanother TV station. Local TV -set os-cillation can be cured only by check-ing individual sets and tapoffs forproper connections. Coax cable in thevicinity of the receiver must be

grounded.Dark moving horizontal bars in pix

may be caused by an improperlytuned TV set. If the set is tunedproperly and bars still appear, thenthe difficulty is due to 60 -cycle ac inthe picture signal. Examine the am -


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plifier for detective tubes, rectifiers,de filter condensers, or other powersupply components. If ac bars appearsin just one receiver, look for actrouble in that receiver rather than inthe line.

Light streaks shooting horizontallythrough pix indicate interference fromautomobile ignition, neon or fluores-cent lights, electric motors, high volt-age power line or internUttant cableconnections. This may be corrected bya high-pass rf filter used at the am-plifier inputs.

A weak signal on some channelswith normal signals on others is usual-ly due to a mismatched, open, orshort-circuited transmission line. Theseline faults occur in such a way as toform a trap for the channels affected.Check all line terminations and con-nections.

The following hints will prove use-ful to the Service Man installing amaster antenna system of this type.First make sure to ground all equip-ment. Use a lightning arrester to saveequipment from possible damagefrom lightning. Make certain that theantenna mounting is structurallysound. Use guy wires when necessary.Finally pay careful attention to allbasic installation techniques, especial-ly soldering. A poorly soldered con-nection may he difficult to locateafter the system has been installed.

n

PORTABLE TUBE TESTER

A MULTIPLE - SOCKET dynamic - mutual -conductance tube tester, 500B Dyna-Quik, with tests for shorts, grid emission,gas content and leakage, has been an-nounced by B&K Manufacturing Co.,3726 N. Southport Ave., Chicago 13, Ill.

Unit shows tube condition on good -bad scale and in micromhos. Life testis said to show life expectancy of tubesin set. One switch is used for all tests.Popular tube -type settings are listeddirectly on socket panels; complete quickreference chart inside cover. Bridgemonitors line voltage for automatic com-pensation. Seven and nine -pin straighten-ers on panel. Further information inbulletin TAD -18. [SERVICE]

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HEATHKITSGIVE YOUTWICE AS MUCHequipment forevery dollarinvestedThe famous model V -7A Vacuum -Tube -Voltmeter is a'perfectexample of the high -qualityinstruments available from Heathat 'A the price you would expectto pay! Complete.

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Get the most out of your test equipment budget by utilizing HEATHKITinstruments in your laboratory or on your production line. Get highquality equipment, without paying the usual premium price, by dealingdirectly with the manufacturer, and by letting engineers or techniciansassemble Heathkits between rush periods. Comprehensive instructionsinsure minimum construction time. You'll get more equipment for thesame investment, and be able to fill your needs by choosing from themore than 100 different electronic kits by Heath. These are the mostpopular "do-it-yourself" kits in the world, so why not investigate theirpossibilities in your particular area of activity! Write for the freeHeathkit catalog now!

Contains detailed descriptionsof Heathkit models available,including VTVM's, scopes,generators, testers, bridges,power supplies, etc.

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HEATH COMPANYA SUBSIDIARY OF DAYSTROM, INC,BENTON HARBOR 11, MICHIGAN

Name

Address

City & Zone

State

Servicing Uprightby E. A. MUELLER

A RECENT REPORT1 discussed the op-portunities in the small applianceservicing and points out that theService Man, because of his retail ex-perience and specialized training, isin an ideal position to develop thisfield as a source of supplementary in-come. One of the most common ofthese small appliances is the homevacuum cleaner, and a few hints ontheir servicing may prove useful tothe Service Man.

As is generally known, there aretwo distinct types of vacuums in thehome cleaning field. The older of thetwo styles is commonly called anupright cleaner, and is operated by ahandle from the motor unit. It hasan exterior bag or dirt container, andin almost all cases employs the prin-ciple of a revolving brush mounted inthe nozzle. The brush is driven bya rubber belt operating from a pulleywhich is in effect an extension of therotor, or armature, shaft.

The nozzle of the upright vac isadjusted about a in. above the carpetsurface, so that in operation the areaof carpet immediately under the noz-zle is lifted by suction into contactwith the nozzle providing an airpocket between carpet and floor. Thisair pocket acts as a cushion againstwhich the revolving brush beats andagitates the carpet to loosen grit anddirt imbedded in the base of the nap.This makes it possible for the suctionto draw air through the carpet, takingwith it the loosened grit. The dis-advantage of the upright cleaner isthat attachments for cleaning edges of

wall-to-wall carpet, furniture anddrapes are clumsy to use and lacksufficient power for straight -suctioncleaning.

A second variety of vacuum is thestraight suction cleaner, either thetank type' or the cannister type.3These cleaners operate on the prin-ciple of straight suction without agita-tion, and necessarily employ a muchhigher degree of suction than theupright style. It is generally muchmore efficient for accessory cleaning,and the attachments are more con-venient to use.

Modern tank units are built withvarying degrees of mobility and utilizea flexible hose, with swivel couplings,to connect the motor and with a multi-

1Small Appliance Service Opportuni-ties, E. A. Mueller, SERVICE, February,1958.

2Such as the Electrolux.3Such as General Electric models.


Home Vacuum Cleaners

Electric Sweeper Service Co

tude of attachment tools. Theoretical-ly, the disadvantage of this type foruse on carpeting is that its lack ofrevolving brush prevents brushing ofthe nap and agitation of imbeddedgrit, making it efficient only for sur-face cleaning.

As these two styles are quite dif-ferent, it is to be expected that theservicing procedures, except for themotors, would vary from one to theother. In this article we will considerthe servicing problems common toupright cleaners. Tank -type cleanersand vacuum -cleaner motors, whichare common to both styles, will becovered in a later report.

Aside from faulty motors, the fourmost common complaints encounteredin servicing uprights are those asso-ciated with the bag or dirt container,the brush and belt, the cord andswitch, and the fan or impellor. Thesedifficulties account for between 60and 75 per cent of vacuum repairsand are far easier to remedy and gen-erally much more profitable than themore difficult motor repairs.

Bag or Dirt Container

The condition of the bag or dirtcontainer ranks first as a troublesource because so few users under-stand its function. A bag must beefficient in two respects. It must beof a material woven and chemicallytreated to retain dust with a minimumof leakage, but it must also be suffi-ciently porous to permit a volume ofair to pass through which is in directproportion to the volume drawn inthrough the nozzle creating suction.If there is, or has been, a moisturecondition in the cloth bags, if the bagis not emptied often enough, or if thepores of the material become dustclogged by long use, then it is possiblethere may be as much as 60% loss inefficiency. These cloth bags cannot bewashed, they must be replaced.

A quick way to test bag efficiencyis to turn on the cleaner and thencompress the bag between the flat ofyour hands. If it compresses easily andwithout effort, the chances are it isin good condition. However, if thebag offers resistance and is blown up"hard," it is definite evidence that thebag needs replacing.

Many uprights are now sold witha special zippered cloth bag whichholds paper disposable inserts. It is

importantANNOUNCEMEabout the TOBE contest a

on the next two pages!Did you know that Tobe is the fastest growing service capacitor linein the U.S.? Even so, we still are getting letters every day fromdealers who want to enter our big 50 -Prize contest (see ad on nextspread) but can't... because their nearest distributor is not yetstocking new Tobe Service Capacitors.For this reason we are extending the Tobe contest from May 30 toJune 30-and making a very special offer besides! We want YOU tohave a chance at that Ford Ranch Wagon, the mink stole and all theother prizes. And we want you to familiarize yourself with Tobe-since 1922 one of America's most popular original equipment ca-pacitor lines.

SPECIAL OFFER! THREE FREE CAPACITORS.Send in your contest entry (entry blank on next page) today...without a boxtop. It only takes a minute to write a good entry. Enclosewith your entry an order for any Tobe capacitor described below. Wewill remove the boxtop and attach it to your entry. Send no money-we will bill you through your distributor. And we will also include,with your Tobe Capacitor, three of our tough little "Tobemite" moldedplastic tubulars for popular applications absolutely free. Send in yourentry-and order as many Tobe's described below as you want-today!

WRITE FOR THESE TOBE SERVICE CAPACITORS TODAY(all prices are dealer stet)

TWIST -PRONG BASE

ELECTROLYTICS

Each witha bakelite anda metal mountingwasher. Popular"Preferred Type" plan.

"JET" ELECTROLYTIC

TUBULARS

Tubularelectrolyticshermetically sealedinto aluminum containersprotected in a transparentred plastic sleeve.

ALSO: Metal Cased Paper Capacitors, Threaded NeckCapacitors. Disc Ceramic Capacitors. Metal CasedTubulars, Phenolic -Cased Printed Circuit Capacitors.

YOU'LL RECEIVE FREE: 3 "TOBEMITE" MOLDEDPLASTIC TUBULARS in popular applications. Theseare America's finest molded tubulars, and they're farsmaller than other equally rated capacitors.

MYLAR *

TUBULARS

Thesebrilliantcapacitors are idealfor use in humid climes-thanks to DuPont's Mylar,world's finest insulation.

`A DuPont Trademark

SERVICE CAPACITORS<ztrO

CLIP THIS ORDER FORM TO YOUR CONTEST ENTRY BLANK (SEE NEXT PAGE)

TOBE DEUTSCHMANN Service Division, 2900 Columbia Ave., Indianapolis 5, Ind.Please send me Tobe Replacement Service Capacitors as follows:

Quantity Indicate Rating & CharacteristicsMylarJet ElectrolyticTwist -ProngTobemite

Please send me the complete Tobe Capacitor Catalog.

FIRM NAME

Remove the boxtopbefore shipping

and hold with mycontest entry

attached.

ADDRESS

CITY ZONE STATE

SIGNED

MY JOBBER IS

I understand I will also receive 3 Tobe Molded Tubular Capacitors absolutely FREE.My jobber will bill me for the other capacitor (s) indicated. (Offer ends midnight. June 30. 1958.)

t5 WORDS

Tell Why You LikeTobe Service Capacitors

Your 25 words can win the Ford Ranch Wagon

And Here Are the TSC* Features to Help You Win Nosubstandard materials can possibly enter the manufac-ture of TOBE SERVICE CAPACITORS, because everything isquality -checked beforehand Highest grade dielectricmaterials prevent voltage breakdown in service TSC'sare designed for high -temperature operation - will notdry out or deteriorate in service Copperweld leadssoldered directly to foil insure you against opensMoisture -tight seals guard against shorts Pigtail leadswill not pull out or break off No danger of hot solderingiron opening internal connection or melting sealing com-pound TSC's will maintain specified capacity over entireoperating temperature range TSC's receive 100%quality -control inspection prior to shipment Continuousproduction -line testing automatically rejects "duds" Maintenance of large inventories on complete line meansfaster delivery to your TORE DISTRIBUTOR and you.

Tobe Service Capacitors fOBE 4t4.11001

CAPACITORS

Tobe Deutschmann Corporation, Dept. C2900 Columbia Avenue, Indianapolis 5, Indiana

"I prefer Tobc Service Capacitors in my work because

NAME

ADDRESS

more convenient for present dayhousewives to discard the paper unitwhen full and zip in a fresh insert.These special zipper units can be ob-tained for all upright cleaners, evenwhere not a part of original equip-ment.

Brush and Belt

Number two source of complaint isthe condition of the brush and belt.Belts are molded of rubber so thatthere can be stretch tension to drivethe brush. Even the best of cruderubber will stretch and deterioratewith age and then no longer drive thebrush. The more important difficultyis that many housewives pick up safetypins, hairpins and similar objects incareless operation of the cleaner. Onepin can slice a brand new belt in two.Make sure the belt is in good condi-tion, and sell the customer an extraone as a spare.

Except for the Hoover cleaner, mostrevolving brushes have a method oflowering the brush within the nozzleto compensate for wear, extending itslife two to four times. Common-senseinspection of the brush -end mountingwill reveal this to any mechanicallyinclined person. For instance, theRoyal brush has a square mountingpiece on the brush end which is offcenter and each side is numbered. Thenumeral 1 is faced up on each endwhen a new brush is installed, andas the bristle wears the ends are turnedone -quarter turn lowering the brush inthe nozzle.

Other makes such as HamiltonBeach and G.E. have spring clip ad-justment in the nozzle mounting. TheHoover, with its barrel constructionand metal bar beater, has no such ad-justment and the bristled metal stripswhich insert into the barrel must bereplaced every six to nine months.The brush bristle in all cases shouldextend about 1/16 in. through (oroutside of) the nozzle opening forbest operation.

Revolving brushes are prone to col-lect thread, strings, and lint, andshould be watched and kept free andclean. It is not unusual for a carelesshousekeeper to bring a cleaner in forrepair with so much thread and lintbound around the brush that thebristle is matted down solidly and thebrush is useless. Care must be takenin checking to make sure the tufts ofbristle are not thinned out.

Cord and Switch

The most common cause of com-plete failure is a break in the cord.Just as preventive service in other re -

CITY ZONE STATE1 enclose a Tobe boxtop

spects is usually disregarded by thehousewife, it is even more forgottenwhen it comes to vacuum cleaners.Cord ages, cracks, becomes brittle andunsafe, and should be replaced whenthese symptoms are noticed. Most fre-quently a break appears at the twomajor wear points, the wall plug andthe switch.

Reconnecting Switch

If the general appearance of thecord is good, and continuity check in-dicates there is a break, a safe pro-cedure is to cut about six inches offthe cleaner end of the cord and re-connect to the handle switch, andabout three inches from the oppositeand install a new spring action rubbermale plug. With continued use switchcontacts and springs will wear and anew switch can be easily installed.

Occasionally, either by accident orcarelessness, a solid object such as asmall piece of gravel, metal screw ornut, or even a chip of porcelain ispicked up and, in going through thefan chamber, chips or breaks one ormore of the blades of the suction fan.This causes the blade to be out ofbalance, and the turning at high speedliterally shakes the unit to pieces.

Fan Blade or Impellor

Almost all fan blades are threadeddirectly onto the armature or motorshaft, and except for Kirby, the beltpulley also threads onto the shaft andlocks the fan in place. In the case ofKirby, the fan and pulley are one -unitassemblies, and are threaded on to-gether. In the case of Hoover, late -model Apex, and Eureka, the fan justslides on the shaft and the pulley isthreaded on against the fan hub, hold-ing it tightly by pressure.

LONG -NOSE PLIERS

INSULATED LONG -NOSE pliers, 8387, forrepairing high -voltage sections of TVsets, have been announced by GeneralCement Manufacturing Co., 400 S.Wyman St., Rockford, Ill.

Pliers are constructed of high -impactplastic, are non-magnetic and will notinterfere with circuit operation. [SERvICE]

IN THISFORD

RANCH WAGONOr one of 49 other valuable prizes

Here's all you do . . . In 25 words or less, tell us why youprefer TOBE SERVICE CAPACITORS.

Then, send your entry to us with the top from any TOBEcapacitor carton, or the plastic box some TOBE capacitorsare packed in.

That's all there is to it. Enter as many times as you wish,providing each entry is accompanied by a TOBE carton topor the plastic box. Use entry blank below. Additionalentry blanks can be obtained from your TOBE DISTRIBUTOR.

Contest closes June 30.

Contest is open to all service -men over 21 years of ageresiding in the continental United States. Employees ofthe TOBE DEUTSCHMANN CORPORATION and their advertis-ing agency are excluded. All entries become the propertyof TOBE DEUTSCHMANN CORPORATION. Decisions of thejudges are final. In case of ties, duplicate prizes will beawarded. Contest closes June 30, 1958. Winners will beannounced July 31st.

TOBE TOBECAPACITORS

Tobe Deutschmann Corporation, Dept. C2900 Columbia Avenue, Indianapolis 5, Indiana

"I prefer Tobe Service Capacitors in my work because

NAME

ADDRESS

CITY ZONE STATE1 enclose a Tobe boxlop

Thoroughbreds whenthe heat's on

Here are two types of C -D tubulars so thoroughly entombed in high-grade plastic that they're virtually unaffected by heat, cold andhumidity. And, because they employ superior dielectrics, these capaci-tors have a 15%-25% greater voltage breakdown margin. That makerthem the ideal replacement capacitors on all servicing jobs.

The C -D CUB, shown, is available with HT COMPOUND or DYKANOL "C"dielectric. The C -D PM utilizes the superior dielectric qualities ofDUPONT "MYLAR." Both types maintain excellent electrical character-istics at high temperatures.

For a lasting service job, use C -D CUBS or PM'S. Your local C -Ddistributor carries complete stocks. For full data, ask for catalog200D-3, or write Cornell-Dubilier Electric Corporation, South Plain-field, New Jersey, Dept. S -58B.

CORNELL - DUBILIERCAPACITORS

ASSOCIATIONS

NATESA

REPRESENTATIVES of 51 Service Men'sassociations attended the NATESASpring Directors Meeting at Spring-field, Mo., on April 27th.

George Crossland of General Elec-tric's tube department spoke to thegroup about Customer Relations.

Another feature of the program wasthe demonstration of test equipmentby Winston Starks, president of Win-ston Electronics, and Norm Peterson,engineer of Kingston Electronic Corp.

Friends of Service Managementawards were presented to SylvaniaElectric Products, CBS - Hytron,Sprague Products Company, HowardW. Sams and Company, and P. R.Mallory and Company.

Subjects discussed by the NATESAdirectors included captive service, li-censing, emblems, membership exten-sion, wholesale abuses, state associa-tion status, phony trade schools, ad-verse publicity, and the NATESA ad-vertising and publicity program.

It was voted to open membershipto all state groups. Fourteen newgroups were accepted as members atthe meeting, bringing the total mem-bership to 98 associations. Plans weremade for the Annual NATESA con-

which will be held at theCongress hotel in Chicago from Au-gust 21st through 24th.

* 0 0

TSG, San Francisco, Calif.

Edwin. R. Hawkins has been elect-ed president of the San FranciscoTelevision Service Guild. Other offi-cers include J. Jerome Strauss, vicepresident; Bill Finnerty, secretary;and Mrs. Gibson Baries, treasurer. Di-rectors for the year are Andy Ceri-sier, Earl Crocker, Ned Gramlich,Walt Kolbuss, Bryant McGrath, JimMiller and Roy Norton. . B. Gross wasreappointed executive secretary.

a * *

ARTS, New York CityTHE Associated Radio -Television Ser-icemen of New York have issued achart of minimum labor rates for 'TVrepair work. Chart is included on asuggested bill form that has been dis-tributed to members of the group.

FRTSA, Pennsylvania

THE Federation of Radio and Televi-sion Service Associations passed aresolution condemning "certain" ra-dio, TV and hi-fi manufacturers for"footballing free labor and service forperiods of up to one year," at a re-cent meeting.

The group questioned the use ofthese policies by manufacturers who

4,

Old Hands at Dependability

fix fees that may be charged by inde-pendent Service Men fulfilling war-ranties.

The group also drafted a letter tobe sent to the Bell Telephone Com-pany of Pennsylvania in which thetelephone company's free service list-ings in classified directories are labeledas "another form of bait advertising."

Milan Krupa was named to head acommittee formed to look into thepossibility of cosponsoring a RadioRepair Month in conjunction with thePennsylvania Broadcasters Associa-tion.

O 0 0

CETA, New York CityAT A recent meeting the CertifiedElectronic Technicians Associationelected Robert Cornell, president;John Hendricks, vice president; NickColon, Jr., treasurer; Charles Baines,recording secretary; Alfred Schab-huttl, corresponding secretary; andGraham Holzhausen, sergeant at arms.

O 0 0

RTA, Pasadena, Calif.

Reese Thomas, general manager ofthe Pasadena Merchants Association,presented a lecture on "CollectingYour Bills" at a recent meeting ofRTA.

o 0 0

ESFETA, New York

AT the annual meeting of the Em-pire State Federation of ElectronicTechnicians Associations Robert Lar-sen was elected president. Other newofficers of the group are Irving J.Toner, vice president; George Carl-son, secretary; Dan Hurley, treasurer;and Frank Kurowski, sergeant atarms.

TTSDA, Benton Harbor, Mich.

William Toth has been elected presi-dent of the Tri-County TelevisionService Dealers Association. RobertWiley was named vice president; RayBlackburn, recording secretary; JimClupper, corresponding secretary; EdRoscher, treasurer; and Carl Janke,trustee.

0

TA, South Oakland County, Mich.THE South Oakland County Televi-sion Association has chosen Sam Bald-win as president. Other new officers ofthe group are John Hengel, vice pres-ident; John Palmer, secretary; andHarold Ingalls, treasurer.

Members of the board of directorsare John Werbinski, Dick Schneiderand Mike Mosier.

Old Hands at Dependability

Built to last...a type for every radio

The C -D brand name on a vibrator is your guarantee of dependableperformance, long trouble -free service. Because C -D vibrators arebuilt to last, you can use them with full confidence. That's why itpays to reach for a C -D when a replacement is called for.

Remember, too, that there's a c -D vibrator type for every make andmodel car on the road. And the C -D VIBRATOR REPLACEMENT GUIDEmakes it quick and easy for you to select the exact type required.Ask your local C -D distributor for a free copy of VIB-3, or write toCornell-Dubilier Electric Corp., South Plainfield, N. J. Jept. S -58A

CORNELL-DUBILIERVIBRATORS

SUCCESSFUL TECHNICIANSRELY ON RIDER SERVICE 'AIDS'

FABULOUS "picture -book" COURSE

NOW AVAILABLEB ASIC TELEVISION, by Alexander Schure. This new5 volume addition to the famous "picture book"courses is the most understandable presentation ofblack and white television receiver theory at thebasic level ever published. It starts with the trans-mitter and discusses in detail the following sub-jects: Volume 1, the transmitter; the handling andthe operation of the camera; formation of thepicture signal and the general content of the trans-mitter. Volume 2 covers the organization of theentire TV receiver treating each section individ-ually from antennas to picture tube. Volumes 3. 4and 5 treat with TV receiver circuit explanations.Each volume covers a specific number of sectionsin the receiver. #198-soft cover, 5 vols. 688 pages$10.00 per set. #198-H all 5 volumes in a singlecloth covered binding, $11.50.HOME AIR CONDITIONING by J. Dermal', H. Sea-man, F'. Makstein. Modern up-to-the-minute textprovides a firm foundation air conditioning theoryupon which the practical know-how for installa-tion and repair can be built. Starting with thebasic physics of air conditioning, all componentparts including compressoas, condensers, capil-lary tubes etc. and their functions are covered.Typical window and packaged installations aredescribed and illustrated. Smaller commercial in-stallations are included. Troubleshooting and re-pair techniques explained. Recent and futuredevelopments in air conditioning covered. Morethan 100 illustrations support text. $3.50.REPAIRING HI-FI SYSTEMS, by David Fidelman.This book deals with finding the troubles andrepairing faults in hi-fi equipment with no testinstruments - simple equipment - and elaborateequipment. Typical troubles are analyzed and re-paired through a system of logical steps. Softcover, 212 pp., illus. =205. $3,90.REPAIRING TELEVISION RECEIVERS, by Cyrus Glick -stein . The most modern completely practical book.written by an expert with long experience intelevision receiver repair. Devoted to trouble-shooting and repair techniques which are modern.yet down-to-earth. Covers the use of simple aswell as elaborate test equipment of all kinds. Pro-fusely illustrated. Soft Cover. 212 pp.. 51," xillus. #191, Only $4.40.3rd SUPPLEMENT to the RECEIVING TUBE SUBSTI-TUTION GUIDEBOOK, by II. A. Middleton. A mustfor every technician! Contains more than 830 latestreceiving tube substitutions more than 200 pic-ture tube substitutions more than 230 Americanto European tube substitutions more than 200European to American tube substitutions a cumu-lative index listing the tube types treated in thebasic book and all 3 supplements. it pays for itselfalmost immediately! #139-3-Soft Cover, 72 pp.,

x 11", illus. Only $1.35.RECEIVING TUBE SUBSTITUTION GUIDEBOOK, byH. A. Middletnn. .t.135-Soft cover, 221 pp..x 11", $3.00.FIRST SUPPLEMENT, =-139-SeFL cover, 48 pp.,x 11". illu- . 5.99.SECOND SUPPLEMENT, 139-2-Soft cover, 48 pp..

" x 11", illus., $.99.

ADVANCED TV SERVICING TECHNIQUES, by Zbarand Schildkraut. A complete advanced TV servic-ing course, developed by the Radio -Electronics -Television Manufacturers Association. Shows howto use every conceivable type of test equipment.how to service every part of a TV receiver. Ex-plains latest techniques. Soft cover. 8,Y x 11".MAIN TEXT, 192 pp.. illus. #161, $3.60.LABORATORY WORKBOOK, 32 pp. #161-2, $.95.TV PICTURE TUBE -CHASSIS GUIDE, by Rider LabStaff. This easy -to -use TV tube type chassis guidecovers all picture tube types used in TV receiverproduction from 1946 to February 1957-over 7.000listings. Organized by chassis number, and in somecases, by models so that the technician can immediately locate the eor,et picture tube type simplyby knowing the chli- -i- number. ±-'204, Only $1.35

RIDER'S NEW S D 0 SERVICE("single diagram only")

ONLY 50c PER CHASSIS AT YOUR LOCAL JOBBER

RIDER'S TV 22NOW

AVAILABLEonly $24.00

Rider books, manuals. S D 0 are available at yourParts Jobber. Look for the Rider Bookseller. Ift --e books are not available, order direct. B-5

V JOHN F. RIDER PUBLISHER, INC.\\ 116 West 14th Street, New York 11. N. Y.

CATALOGS BOOKSCHICAGO STANDARD TRANSFORMER CORP.,3501 Addison St., Chicago 18, Ill., hasissued a wall chart, DH -1, listing Stancorreplacement flybacks and yokes by orig-inal manufacturers' part numbers. Setmanufacturers are listed alphabetically.[SERVICE]

* 0

GENERAL ELECTRIC Co., TelevisionReceiver Dept., Syracuse, N. Y., haspublished volume 3 of G.E.'s TV ServiceGuide covering TV receivers manufac-tured from 1955 to 1957, including the110° line. Also contains production -change information and component -location diagrams. Features included area photo index; schematic diagrams ofchassis, vhf and uhf tuners; a replace-ment parts list of appearance items, elec-trical components and main chassis;diagrams describing tube and trimmerlocations as well as test points in bothtop and bottom chassis views. [SERvicE]

O *

NELSON PUBLISHING CO., P.O. Box 36,Redding Ridge, Conn., has publishedTelevision Interference, Its Causes andCures by Philip S. Rand. Book is dividedinto 10 chapters covering TV interferencesources and types, locating interference,TV receivers, transmitters, shielding andfiltering, special vhf problems, design anduse of high and low-pass filters, externalharmonic generation and industrial,medical and public -utility interference.Included is a bibliography, list of TVinterference committees, frequencies ofamateur band harmonics, table of U.S.TV channels and frequencies, tables ofworldwide TV standards and channelsand excerpts from FCC rules. -56 pages;priced at $1.75. [SERVICE]

a 9 a

ELECTRONIC PUBLISHING CO., INC., 180N. Wacker Drive, Chicago 6, Ill., hasissued a new edition of Dave Rice'sOfficial Pricing Digest with resale pricesfor over 63,000 replacement parts. Atable of flat rate and hourly servicecharges showing regional and nationalaverages is included. Price data arearranged alphabetically by manufacturersand products numerically by part num-ber. Priced at $2.50. [SERVICE]

a * *

Eico, 33-00 Northern Blvd., Long IslandCity 1, N. Y., has released a 16 -page il-lustrated catalog, C-158, covering an FMtuner, preamplifier, integrated and poweramplifiers, bookshelf and floor speakersystems, vtvms, voms, 'scopes, tube andtransistor testers, signal and sweep gen-erators, battery eliminators, substitutionboxes, flyback tester, battery tester, RCLbridge, electronic switch, voltage calibra-tor and accessory probes available inboth kit and wired form. [SERvIcE]

a * 0

GENERAL ELECTRIC CO., SemiconductorProducts Dept., Syracuse, N. Y., has re-leased a 4 -page illustrated brochure,ECG -292, with specifications and per-formance graphs on 2N43 and 2N44germanium alloy junction transistors.[SERVICE]

installing TV antennas?for the right accessories

to do the best job

you'll find itfaster in the

ASTERnew 1958 edition -world's largestelectronic' catalog only *3.50 atyour local parts distributor-nowFree! Write for Panel Lamp Chart.

THE RADIO -ELECTRONIC MASTER60 MADISON AVE., HEMPSTEAD, N. Y.

Cut Down Cal Backs...

INSTALL A WUERTH

SWRONWRON EVERY SERVICE CALL

G -C Wuerth No. 5301...For Black & WhiteTV List $1.65

G -C Wuerth No. 5302...For Color TV Sets

List $1.95

Stops harmful voltagesurges to picture andradio tubes. Sell yourcustomers tripled tubelife and you'll profiton each installation.Simply connect directlyinto power line.Functions like acombination resistor -relay to preserveelectrolytic capacitors,dry disc rectifiers,transformers, pilot bulbsand other componentsas well as tubes.

Available righ now Irons your localelectronics parts distributor or

write direct to:

G -C ELECTRONICS MFG. CO.division of G -C TEXTRON INC.

Western Plant: Los Angeles 18, Calif.Main Plant, ROCKFORD, ILLINOIS, U.S.A.


PERSONNELCONVERT TV PROBL MS

INTO PROFITS !ADVERTISERS IN SERVICE

MAY, 1958Page

Alliance Manufacturing Co., Inc.Insiee Front Cover

American Television and Ratans Co. 411

Amperex Electronic Corp. 27

Argos Products Co., Inc. 2

Atlas Sound Corp. 31

B&K Manufacturing Co. 20

Blonder -Tongue Laboratories, Inc. . 26

British Industries Corp., MulticoreSales Corp. Div.

Bussmann Manufacturing Co. 639

Centralab, A Div. of Globe -Union, Inc. 3

Cleveland Institute of Radio Electronics 33

Cornell-Dubilier Electric Co41r.p,42, 43, 44, 45

EICOElectra -Craft Appliance Co.Electro Products LaboratoriesElectro-Voice, Inc.ESSCO, Inc.

Fast Chemical Products Corp. 39

FidelitoneGeneral Cement Manufacturing Co ,

Div. of Textron, Inc. 37, 39, 46General Electric Co., Electronic

Components Div. 25

Heath Co.

Jensen Industries, Inc.JFD Electronics Corp.Kester Solder Co.

374832

748

31

40

2828, 37, 39, 47

36

Moss Electronic Distributing Co., Inc 35

Oxford Components, Inc. 30

PGrma-Power Co.Precision Electronics, Inc. 30

Pyramid Electric Co. 23

Radio Corporation of America, ElectronTube Div. 22, Back Cover

Raytheon Manufacturing Co 8

Recoton Corp. 32

John F. Rider Publisher, Inc. 46

Service Instruments Corp.Sonotone Corp.Sprague Products Co. 17

Sylvania Electric Products, Inc. 4, 5

Sarkes Tarzian, Inc., Rectifier Div. 34

Tech -Master Corp. 36Tobe Deutschmann Corp. ..41, 42, 43, 44, 45

United Catalog Publishers, Inc. 46University Loudspeakers, Inc.

Inside Back Cover

38

Xcelite, Inc.

4729

38

Zenith Radio Corp. 1, 12, 13

MULTIPLE -SOCKET TUBE TESTER

A 41 -SOCKET tube tester, FC-2, has beenannounced by Century Electronics Co.,Inc., 111 Roosevelt Ave., Mineola, N. Y.

Two settings are used for quality, inter -element short and leakage, gas contentand life expectancy tests said to checkmore than 600 tube types. Circuitry hasbeen designed to accommodate newtubes without modification; new listingsare issued periodically.

Uses D'Arsonval type meter protectedagainst burnout. Tester is line -isolatedand line -voltage compensation is in-cluded. Has 7- and 9 -pin straightenerson panel. Picture tube adapter cableallows unit to be used as a picture -tubetester -rejuvenator for all picture tubes in-cluding short -neck 110° types. [SERVICE]

ROBERT t.CHSLER has been namedadvertising, sales promotion and pub-lic relations manager of AmericanGeloso Electronics, Inc., 312 SeventhAve., New York 1, N. Y.

O 0 *

THOMAS & SUKUP, INC., 5226 N. Key-stone Ave., Indianapolis, Ind., hasbeen appointed as representative forAmperex Electronic Corp., Inc., inIndiana and Kentucky.

*

GERARD CAFARO and GEORGE KULPERhave been named sales engineers forthe rectifier division of Audio Devices,Inc., 444 Madison Ave., New York 22,N. Y.

O 0 0

AMES F. GIORDANO has been ap-pointed chief engineer of Blonder -Tongue Laboratories, Inc., 9-25 AilingSt., Newark 2, N. J.

* 0 *

ROLAND A. REUTHER has been namedassistant to the vice president ofCleveland Institute of Radio Electron-ics, 4900 Euclid Ave., Cleveland 3,Ohio.

O 0 0

ROBERT G. FURLONG has been ap-pointed sales manager of the tele-vision receiver division of Allen B.Du Mont Laboratories, Inc., 750Bloomfield Ave., Clifton, N. J.

* *

DoN JONSON has been named salesmanager of G -C Electronics Manu-facturing Company division of G -CTextron, Inc.

O 0

PETER HUMENIUK has been appointedmanager, engineering of the televisionreceiver department of General Elec-tric Co., Electronics Park, Syracuse,N. Y.

O 0

JOSEPH R. OWEN has been namedmanager of advertising and sales pro-motion of the specialty electroniccomponents department of GeneralElectric Co., Syracuse, N. Y.

O 0 0

JOHN A. MCCORMICK has been ap-pointed manager of system sales fortwo-way radio units, communicationproducts department, General ElectricCo., Syracuse, N. Y.

O 0 A

JERRY MELTZER has been named salesmanager of the newly formed Gen-eral Instrument Distributor Div., 240Wythe Ave., Brooklyn 11, N. Y.

* 0 0

D. 0. REINERT has been named man -ager, mobile and microwave service

RCA Service Co., Inc., Camden 8, L

5-4.0

FD

OUTDOOR

ANTENNA COUPLERS

SERVICE SAVERS

vnr

:4,13

Combine any Hi -Lo VHF, UHF -VHF orHi -Lo VHF -UHF antenna into a singleweather-proof system using one down -lead. Low loss R -L -C networks (bandpass, high pass and low pass combina-tions.) Fast, secure U -bolt mounting. Noclumsy straps. Write for Service -SaverBrochure showing 40 money -making TVaccessories now at all JFD distributors.

model listantenna systems

AC10 Joins Ch. 2-6 to 7-13 $3.50AC20 Joins Ch. 2-13 to 14-83 3.75

AC30Joins Ch. 2-6 to 7-13to 14-83 4.85



1"1"lam

I NEW! 111111'110110!SENCORE

TRC4

TRANSISTORCHECKER

America'snewest,

most popular test

instruments

NOW CHECKS:* Transistorsfor opens, shorts,leakage and cur-rent gain. In-cludes newgain test onPower, transistors.* Crystal Diodeschecks forward to reversecurrent ratio on alldiodes.* Selenium Rectifierschecks forward and re-verse currents.

14iControls are accurately 'tset for each transistorby referring to replaceable set-up chart on iear.Test leads or socket provides for fast hookup.

See your ports distributor.

sales, technical products department,eimENCOR w 1ir Tyg SERVICESE

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1

IINSTRUMENTS CORP. I

171 OFFICIAL RD., ADDISON, ILL.ad now for further information

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eve ,R-"-*.easseelP11.0"""""me".'

tape recorder P. A. system portable TV set hand tools

FROM YOUR CAR, Boat or Plane!

with

INVERTERSFOR CHANGING YOUR STORAGE

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EXECUTIVES POLICEMEN SALESMEN REPORTERS OUTDOOR MEN FIREMEN

PUBLIC OFFICIALSMODELS 6U-RHG (6 volts) 125 to 150 watts. Shippingweight 27 lbs. List price $89.95

DEALER NET PRICE ..... $59.9712U-RHG (12 volts) 150 to 175 watts. Shipping weight27 lbs. List price $89.95

DEALER NET PRICE $59.97Write for literature on other Sizes and Modelsof ATR INVERTERS, priced as low as $9.95 list.

SEE YOUR JOBBER OR WRITE FACTORY&/NEW MODELS ,/NEW DESIGNS -VNEW LITERATURE

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AMERICAN TELEVISION I RADIO CO.

2ualely Pladucta Sere e 1931SAINT PAUL 1, MINNESOTA, U. S. A.

AUREL G. PETRASEk has been pro-moted to manager, merchandising, re-ceiving tubes, RCA Electron TubeDiv., Harrison, N. J.

GEORGE SAPIN has been appointedmanager, advertising and sales pro-motion-entertainment market, RCAElectron Tube Division.

* * *

ROBERT L. SHAW has been namedgeneral marketing manager andHARRY H. MARTIN general manufac-turing manager of Sylvania HomeElectronics, Batavia, N. Y.

* * *

MERLE W. KREMER has been ap-pointed vice president and generalmanager of the parts division of Syl-vania Electric Products, Inc., War-ren, Pa.

* n *

RAYMOND H. HILGERS has been nam-ed sales representative for the mid -west region of the electronic tubedivision of Westinghouse ElectricCorp.

* *

HARRY SCHECHTER has joined ZenithRadio Corp., 6001 Dickens Ave., Chi-cago 39, III., as merchandising assist-ant to the vice president and directorof sales.

*

JOHN K. RUSSELL has been appointeddistrict sales representative for Cleve-land, Detroit, Columbus, Grand Rap-ids and Saginaw by Zenith RadioCorp.

* * 0

HARRY RONAN has been promoted tomanager, two-way radio sales, for thecommunications and industrial elec-tronics division of Motorola, Inc.,4501 W. Augusta Blvd., Chicago 51,Ill.

* *

ROBERT B. MEANS has been appointedmanager, western district, entertain-ment sales, of the RCA Electron TubeDiv., Harrison, N. Y.

* * *

H. J. BENHAM has been appointed man-ager, central service region, technicalproducts service department of RCAService Co.

* *

CHESTER A. GRONDZIK has been namedworks manager of Entron, Inc., 4902Lawrence St., Bladensburg, Md.

a * *

NORMAN CAPLAN has been appointedmanager, communications products de-partment, telecommunications division,RCA, Camden, N. J.

* * *

ROBERT M. BOWIE has been namedvice president of Sylvania ResearchLaboratories, Bayside, N. Y.

PORTABLE APPLIANCE,SERVICE FOR INCREASED

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IRON & TOASTER CORD SETS #16-2 HPT, 7' LONG. HEAVY DUTY. MOLDED PLUG. LEGS

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NEW YORK 36, NEW YORK

CONTACT NEAREST SUPPLIER!


To AVOID amplifier andspeaker WASTE... choose from

alkeis*WIDE-ANGLE

SPEAKERSFor uniform dispersion of sound over a wide area

CHOICE OF 5 DRIVERS FOR CLH OR COBREFLEX

CLN 41/2 ft. air column. Exclusiveomnidirectional bell and mountingbracket helps "tune out" reverbera-tion and "dead spots." $44.50 list.

COBREFLEX All die-cast aluminumone piece construction resists a

life -time of physical abuse. 21/2 ft.air column. $38.33 list.

CIB Built-in hermetically sealeddriver.Excellent for"talk-back."Exclusive Positive-Lok omni-directional mounting bracket.$42.00 list.

CMIL Smaller than CIB, perfectfor voice. Built-in driver packsmighty wallop at low input pow-er. Ideal for close quarter in-stallations. $29.75 list.

MA -25 $27.50 list85-6500 cps. 25 W.

SA -NF $36.00 list80-10,000 cps. 30 W.

SA -30 $47.50 listbuilt-in matching trans.80.10,000 cps. 30 W.

PA -NF $47.50 list70-10,000 cps. 50 W.

PA -50 $57.50 listbuilt-in matching trans.

70.10,000 cps. 50 W.

Only University gives you the choice of speakers you needto ensure greatest economy of amplifier power, equipmentand installation costs. No wasteful, "cure-all, do -all" com-promises here. Each speaker is designed to do its specifickind of job most efficiently and reliably, with plenty ofroom for future expansion. Each speaker incorporatesmany exclusive features to fulfill every possible applica-tion. The chart below graphically shows the relative differ-ences between these four speakers in terms of sound out-

put, input power, and low frequency response. Simplychoose the intended application and determine the appro-priate speakers. Or, depending upon existing operatingprerequisites, select the speaker(s) capable of doing thejob. That's all there is to it.

NOW AVAILABLE-Free Product Catalog. Or send $ I forthe NEW 64 -page University TECHNILOG, the completespeaker system planning manual. Desk X-4, UniversityLoudspeakers, Inc., 80 S. Kensico Ave., White Plains, N.Y.

inh m a.."tiehnilog

BackgroundNoise level

in 110

90

80

75

70

65

60

55

Average TypicalApplication

CHART

FACTORY (Very Noisy)

MACHINE SHOP (Average)

PRINTING PRESS

BALLROOMS

RESTAURANT (Noisy)

NOISY ASSEMBLY DEPT.

FACTORY (Average)

R.R. WAITING ROOM

AUDITORIUM (Average)

ASSEMBLY PLANT (Quiet)

SHIPPING-REC. (Average)

OFFICE (Busy)

DEPT. STORE (Average)

AUDITORIUM (Quiet)

RESTAURANT (Average)

STORE (Quiet)OFFICE (Quiet)GARAGE

HOTEL LOBBY - HOSPITALSCHURCH -FUNERAL PARLOR

CHART

CLH-120 cps

HORN LOW FREQUENCY CUT-OFF*

COBREFLEX-200 cps C18-300 cps135

130

125

E 120cc

col

2 115

t 110coy

m

m105

PA-HF1

(SA -50)

,ar4,1111

SA HF (SA -30)

-25

INPUT

CMIL-400 cps

Extra copies of thisdesign chart availableFR EE upon request.

WATTS 10 20 30 40 50 10 20 30 40 50 5 10 15 1 2 3 4 5

*if input program response limited to above horn low frequency cut-off, input power can be doubled, for 3 db increase in sound output.

HOW TO USE THIS CHART1. Determine sound pressure needed by finding noiselevel from Chart A, add loss of db in Table C and add ad-justing factor in Table D.2. Draw horizontal line across Chart B corresponding tothe db figure just calculated. This now establishes whichspeakers can be considered.3. A vertical line drawn to the base of Chart B shows theinput power needed for each qualifying speaker.4. Now, further selection may be based upon frequency

LISTEN

response necessary (see Horn Cut -Off, Chart B), initialcost, operating economy and reserve power desired.5. The CIB and CMIL may also be used in high noise levelsby employing several throughout the listening area.Example: Factory - noise level 90 db, 320,000 cu. ft., live

acoustics, music and speech90 +25-1 5,-120 db required

Qualifying speakers are CLH or Cobreflex, with any of thedrivers. Final choice is determined by driver characteris-tics and installation problems. (Send for TECHNILOG orProduct Catalog.)

al vits2 stsywuk 6e0it,

TABLE C INDOORS OUTDOORS

ROOM VOLUMECU. FT.

DB LOSS FURTHESTDISTANCE FT. 03 LOSSLIVE NEUTRAL DEAD

1.000 0 3 6 4 0

3,200 5 8 11 8 6

10,000 10 13 16 16 12-32,000 15 18 21 32 18

100.000 20 23 26 64 24

320.000 25 28 31 128 _ 301.000,000 30 33 36 256 36

TABLE D INDOORS DB OUTDOORS DB

PROGRAMADJUSTINGFACTOR

SPEECH

MUSIC 6

7

FMUSIC & SPEECH 5

11

9

You are invited to see us in Booth 871 and display rooms 542A -544A during the Electronic Parts Show, at Conrad Hilton,Chicago. May 19-21

How RCA builds specialprescription grids...extends 6AF4-A life!

RCA's redesign of the 6AF4-A has resulted in minimized slump, product uniformity,and projected average life of 4,000 hours or more!

Here are some of the materials RCA "prescribes" in manufacturing the new 6AF4-A. Thegrid is plated with Palladium, a rare mtal capable of withstanding high temperatures.The use of this grid structure minimizes interelectrode leakage, prevents gridloading, and as a result, provides stable tube performance. The cathode,a nickel alloy, is specially selected to reduc interface resistanceand thus minimizes slump. The use of pins which are silver-platedreduces skin effect at ultrohigh fAuencies and improvestuner performance.

All these features, in addition to dynamic life tests, help to assurelong and dependable performance. No wonder RCA's 6AF4-1k is tops!

So, here's the #1 lesson in radio, phonograph, and TV service-when ordering tubes for replacement, specify "RCA Tubes only."

RADIO CORPORATION OF AMERICAElectron Tube Division

rti) Harrison, N. J.

Documents

ELECTRONIC PARTS E RV C - americanradiohistory.com€¦ · BUSS fuses help you avoid adjust-ments or call-backs that cut into your profits. BUSS fuses can further help you maintain