H N 111.31 Jr- - World Radio History · 2019. 7. 17. · 01110_ 611 (Mt Of VIII 8(C1 160 501 we Rio 100 Ia C410 C414 160110 240 ILF 2000 2000 33 10001 < 112 6804 R3 6808 C3 IS v 501

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Help stamp outblue people

Focus on Jerrold Paralog PlusTMColoraxial Antennas

for true color

Jerrold Paralog Plus Anten-nas show a definite improvementin the sharpness, fidelity and colorstability of the image on any TVset. Sharp directivity, uniform re-sponse and perfect matching seeto that! And the rugged construc-tion insures that the quality stays

high-not for months-but foryears. It's the high -gain Coloraxialantenna for people who insist onVHF and FM reception-withoutcompromise. And there are sevenmodels to choose from.

The Paralog Plus is one of acomplete spectrum of problem-

solVing Jerrold TV receptionaids-Pathfinder, VUfinder andColorpeak antennas... Powermatepre -amplifiers, amplified -couplersand splitters ... Coloraxial cable,wall outlets and wall plates. Seeyour Jerrold distributor today.Catalog available on request.

JE111011)Focusing on one thing-

better reception

... for more details circle 102 on postcard

GROUP

180

ELECTRONIC TECHNICIAN

rfrff.=,"COMPLETE MANUFACTURER S' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 6 NEW SETS

SCHEMATIC NO. SCHEMATIC NO.

AIRLINE 1100 MAGNAVOX 1103Color TV Model G1-11-8247A,57A Color TV Chassis 1920 Series

CANADIAN GENERAL ELECTRIC 1101 PHILCO 1099TV Chassis M649 TV Chassis 1 7C21,A,V,AV

CORONADO 1102 RCA VICTOR 1104TV Model TV 21-9367A TV Chassis KCS165 Series

ontIT41ICI OUST

M.Oft TIM FUNCTION

PIN 111111121

44 1 I 9 SO II II

VI 510:11 to. D... 0* alin 1. 1,11. NOR In a sa

Vt WTI ..... Imo &Or. .IC 94t too 1 or .... etk. on 9 K.. ,c.91 WU 4.1.19..... vianV.,. ... An iw nw

V1

VI

(1111us.lute

is Ir....vw. ow.

)04 sa ) vs r.s ), )00 )sata en v..... A Am 144 POI 1 NO 1 DOS In an )stst en ,),

91 we ft...a.. no a 10 aa.4 III. I'll NM ...ew gaol on.

WI Ole . v.. er owl gee. 005 eit. vit. on. ,a.9 sw to

TI NW . .4.. N. , twep en too , , an ose) or en

TT IOW Pr. revrr ros vs r op r r r en sow we rot P....

Omoo

SYMBOL DESCRIPTION

YHsLOPART NO

C4I - 240/240/160/SW/200v 8+ filter (17(21 .6 21A) 30.2601-33240/240/160/SA1/200v B.- filter (17(2IV & 21AV) 30-2601-49

DI - dual phase comp 34-8037-1D2 - I N60( 2nd det 34.8022-61.1 - 180mh CRT cathode (17(21 & 21A) 32-4762- 7

18Ornh CRT cothode (17(21V & 21AV) . , 32-4902-10L2 - 390mh video plate (17(21 & 21/1) . .. . 32-4762.11

39Ornh video plate ( I 7(21V & 21 AV) 32-4902-14L3 -good sod det 32-4876-114 - sad IF 417(21 & 21 A) 32 4745.13

sna IFSi7L2IV & 2IAVI 32-4745-121.5 -4.5MHz trop and sod takeoff 32-4688-14L7 - tuner cplg 32-4652-10118 - 1st IF plate 32-4686-34L9 - ch 6 beat video det 32-4645-7110 - horiz stabilizer 32-4754-3111 - RFC 60MHz dumper plate 32-4112-63112 - 47 25MHz trap 32-4652-78L13- 41 25MHz trap 32-4652-80LIA - 1st grid pole 32.4652-79115- 47 25MHz trap 32-4652-78L16 - 40MHz choke video det 32 4837.1117- video det cod 32-4652-79118 - 2nd If plate 32-4652-781.19 - RFC 60MHz dormer cathode 32.4112.63Ni - retrace suppress 30-6024-9N2 - red integrator 30-6030-12N3 - hoot osc 30-6057.1N4 - phase comp 30-6035-2R20 - 5 6K 3vr video plate 33-1363-39RV1 - voristor 560v @ lOma vert out 33-1373-6f 1 - 5 611 fusistor 33.1366-21

- audio output 32-10013-5- filter choke 6 hy (17(21 &21A) 32-10010-10

filter choke 6 by (17C21V A 21AV) 32-10075-1- hoot output 32.10008-8

V.O.T.vert output 32-10012.9VR1 - 500K v size 2M v lin 60K H hold 33-5596-16VR2 - 500K vol & on -011 sw 33-5619.22VR3 -- 250K brightness 33.5619.21VR4 - 15K controst 33-5619-20VR5 - 135K vert hold 33-5619.23

Vlf trop ossy w/comp (module -A-) 38-10213VII trap panel less/comp 27-10561.9VII del asst' w/comp (module .8) 38-10214yoke & tome ossy 76-12942-9tuner UHF 11152B (all chassis) 76.13827.2tuner VHF T1170 (17(21) 76-13978-1tuner VHF 1116413(17(21A & 21AV) 76-13945.3tuner VHF TTI64( (17(21 VI 76-13579-8

1351

MODULE T (4? 1511(1

1..,--t-r--.--' I

24 2

CIO -C38 L13

1- 61II

141775 I 41775C39

H23::

31500I

NC NC 39

1-- I

5%C28

LT1 T T 6 /1

bait441

L J F)1-

833

NI

111(1 ARC1+ IV 111 MAL- 110516411

I ARC IPITI- II et SICIAL- IV I/SICIAS)

111

1

180

641VT

15K4E111

151. LT

441

220

C26 R4

1500 6808

00/I MI 10115 PILOT LIM

ItC21 111/0 0111

11C214 111141 vSE110218 TT164C QUIT

11C1141L TIINI

111 NMI 01254 OMIT

MODEL YIN 108E1

ALL 111521

It, estse.

112

22

4000

rn 3111 iTe

46.,L _ _ 134 Jrisr

L _331.

V2T VIT I

3005 5C.17

S 4 4 5

OF TOO = j,st I WAR COAST 1.3911

S1

OFI-ol Ft.

01110_ 611

(Mt Of VIII8(C1 160

501

we Rio

C410 C414160110 240 ILF

2000 2000

3310001 < 112

6804R3

6808

C3

ISv

501

443 'C31 C29

3303 1500- 1500

442Al

14

II

P

sON.0 09.301.

1 4 Volts p/p, 2 4 Volts p/p,15,750 cps 60 cps (max(max contrast) contrast)

77,7 50 Volts p/p, 8 48 Volts p/p,

15,750 cps 60 cps

1514 Volts p/p,15,750 cps

1611 Volts p'p,15,750 cps

:1,44411

3 90 Vclts p/p, 4 80 Volts p/p,15,750 cps 15,750 cps(mar contrast)

5 80 Volts p/p, 6 50 Volts p p,60 cps 60 cps

77,9 60 Volts p/p, 10, Volts p p,

60 cps 0 cps

/

1099PHILCOTV Chassis17C 2 1,A,V,AV

AUGUST 1967

111000 Volts p/p 1 "55 Volts p/p, 138 Volts p ptotal, 180 Volts 60 cps 15,-50 cpsp/p, sawtooth,60 cps

1745 Volts p/p, 18.1+ Volts p 1985 Volts p p,15,750 cps 1+.-s0 cps 1,-50 cps

OSCILLOSCOPE WAVEFORMS

11V1411 Volts p/p,

15,750 cps

These waveforms were taken with the receiver adjusted and 3 where contrast was at maximum. The voltages given arefor an approximate output of 4 V p/p at the video detector. approximate peak -to -peak values. The frequencies shown areVoltage readings taken with raster just filling screen and all those of the waveforms...not the sweep rate of the oscilloscope.controls set for normal picture viewing except for photos I, 2, All readings taken with Model PS127 Sencore Oscilloscope.

35r

VS

2110 IftS5r

645#

0341I

100 1500C32560

)1

1hrI.

r

L

;11445 560

NODULE '1" (DETECTOR/

1300 LIE

1

12:--13,,

LII LIT is

8322500E1

IP

1

163

1454L

L9

4 5(

3188 !IC 110 I v TAKE 631

TRAP offI

2 1.5 30- .1

1

1

1

1

or

434

4

r-77- sir2 661184

1 40

,fr

_1 C14

1°I

830

150

It

7 L,i I

-4- C9

820;RIO>4111

219

M1SOYA

I

-s-

Cl201

R9 MC R322 2 11 Ulf N21 33KfTilifist --"'

2009 1ssrisocTsm sec MN 51111/50

KIT I CS6006 1000

Vt1/2 10118

CAMACC

42415K

NISl'A')

IISS

IC18

1119

228

023PIC

P

114

I/2 6C0IASYNC SEP

1116

6331508

RII391

1450

510

C11

680

431

INN

R25

22K

CI68200

finW ffiff - 1L _ _ _ J

MEI

III

saunaElse

M II

861

151

28

Fl560 C43

680

100 Coe

20041401IF

118(11

1408

+1450

L6390

8343 38

R21

684

6

1150821

+1451

1 8281121I

2R2028K 82

'564M'

64 VSK

II4

}85

1

311 CONT.T c,

L2 R26 NIT 2004390

4 212° V21/210118

VIDEO

OUT

III

25r

0123901

108 005 004 1

IF 6-SI

_ _ _ z_ _14 1504

21,y_AID

I 04/ t-1200 681:14

51 -1121q 0011

6)110

I J

I

PNASE COMP

114 424

V9 42 04 VI 03 VS VT 00 96 CRT 921 VIII

380E1 1011 6C480 4C56 12015 111/8 4E111 4E11 8001 128UP4I

305 5118

2 1 5 4 5 3 4 4 3 12 I 4 5 1 5 4 5 1 I

1114 835C35 C56 C37

I500

T-11500

T1500

4

LYNf TUNER5(E all OAF 005)

UMF tUNEI

R61

1131 -

I140v C240039

651 -1000 Lio126 101 -..

CII015

boos

C22 C23

68 390

10815%

151 2

VIIf 0/NOR

OSC

_ 0303900

000

s-,410

1131

1

C

TP

25r

10

-941

.F440 1152

820 681

; 461101,

NOR HOLD

816.4/8:

116

All390(

849

01111

2 211

2N

VERT

LIN

r Tos-'

221

.(555555' *5555

20400 Volts p p, 2150 Volts p/p,15,750 cps 15,750 cps

Inv

I C5 C4 1 86

110003300 150184 AU010

TO

L 1 012

180 UK

1115

221 r

V13250s

181(101

Sr

Vs1/211118 1

VERT

OSC

to

MIS

5001VOL

9922,5

NI/

1 'cok 1?110

14/330

s

2 81L _ _

42682

221

1454

1124 1+215 r1

826 1+10011 FOCUS

CT cis

SOUADAC

CRT

12E104 01121001

MY

r

11

1IC21A A 11C2144

1018

C 1 1110(5 ARE NOT

NECNANICALLT

NitERCNAKEAILE

kg.

1391500

+140V Ill

901

R29821

-15VC10

01

1254

CIS

1500

0851351

VERT INV,

z , NOR D.68.01:10401

953

1/2 93981111

'5"I

OUT(--3300 tl

"

I 3.91 3300 112

ill 3 8_ !o- 186 C25

8001 220

NOR 1.10%OSC

"DIN401451COLE

+1459

00*840

C21

068 u200V

)C13

033400V

112I1101

631 f 449"

1001 8208

822C33041

654 850211 41N

II IIN30

R55

221

831

tt-f-

VR1A5000VERT

SIZE

4362.21

1.1

VS

1/21/.128VERT.

OUT

Ivan

019041

60041 891II

560114810 MA

1138

100Ia

;11593 9

M25

N 0 Ito

+1409

460

910 4/I1(3 119

141IREC RFC

IC44 (21

18054V 13

3'1;5111116 80

te N 5 CelCull loll

101

II

NV (MI

V(IT

TORE

00 10! NI WAN

V9

,52 300(1

DAMPER

CIO LIIR353022 RFC

3 31I 6009

1121

1099 COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN omBWAY BUILDING. DULUTH. MINNESOTA 55802

1100AIRLINEColor TV ModelGHJ-8247A,57A

III 35V P -P15,750%

16

11111111 10V P -P

11310 15,750%

F

INPUT

O

ELECTRONIC 1-7 rif VE=11 ArTECHNICIANAUGUST 1967COMPLETE MANUFACTURERS' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 6 NEW SETS

I25V P -P

60%

17

9 V P -P

15,750%

7 201SOUND TAKE -OFF

TRANS

R204R236 L2I3 L2I2 150610K 3901 'BUN

4-14-4C233

10D 201

L 211

12011

-14.C"D 1204'ST PIP IF GRID

TRANS

ADJ 47171&A'y(TO VHF TUNER) 22491t216, 15K

SOUND

IREAJE0,C7

L2014725 17

IM`0J2400129.18 I

SR224 R220 zC211220K 100K 001

230V

TO vHF TUNER

265v

R10350K

CG3

rNORM,

27334" "

12-8 1120,0 0

i° J237u _J204

I C221 _R222068 330K

*R2171390K/AAR21,1

12212 R259

,2,3 47K

12213O

2 904

O

100K

C2200

L _

C228.I 541

R201270

0201

6JC6SOUND IF

ill- 4 5VP-P

15,750%

1202 V202SOUND IF

TRANS 6HZ6r IF--, SOUND DEMOD

5 C2076A 560J

202 C20301 820

C204

II

2

R203 82068 20 270

211 C21201 01

'Sr

1203SOUND DE7

TRANS

68

R205 82093.3K 4706

1ST PIP IF

7205 V204IST IF PLATE 6JC6

TRANS 2ND FIX IF

18

1

DI

82193K I

C222 R2233,3 330.._

17

fR221 ,... R22747

C218-7- R225ISO

001i6.88

R2601508

R2I5

2208

C215

T2062ND PM IF PLATE

TRANSD202

50V P -P

60 %

11 )/ P -P

60 %

O950V P -P

15, 750%

II

230V P -P

15,750%

1S13)90V P -P nr

15,750%18- 5V P -P

1255, 07 V5

P

0 L15,750%

TELEVISION WAVEFORMS

C 210.0068

JGJ 12021

5740

10209 R207.0560K -I

TUNER 8RKT 12-3047

0 400V GROUNDS wire-J201

1

TO CHASSIS.R./40V

e

NOTE USE LOW-CAPACITY PROBEWHEN OBSERVING WAVEFORMS

12-12

O30V P -P

15,750%

12

70V P -P15, 750%(EXPANDED)

130V P -P

5,750%

71031-

0'11

AuDIOTROUANTSPUTL 1(3 AUDIO OUT6B05

--""'1709 4'746

2 0

1, 9SPEAKER TERM

Kv2708

240V

'ff°I

AY

12-10

R1300,177E5VOLUME

L205 12164 5 MC TP201TRAP

C236 ISO

8230 C234128 240 C2391

C238 L206 56 t R23539 uN 68K

R233

J211

020581/2 6GH8A

1ST VIDEO

C235

R23110K

4,

R241 118027K

3IJ ,225

I C231

001I474 I2K

2226-

405VV2054

V2 6GH8A8131SYNC - AGC- CHROMA AMP

J218 15K,5*

R23468 MEG

1214

60

J229,,2217 I

R13215K

SW

V20641/2 6GH8A

AG C

8261

12 MEG 7

R258 C240150

R265 C241 R25039K .0033 4 7061M' N AA,

82518264 5.618K MEG

V20681/2 6GH8A

SYNC SEP

2232

824218K,I8

V2009V2 6GF7AVERT OSC R285 R287

4711 82K2

C265027 v.8.

I 0264 ( 1C272 _C r2701C273/Rv20i

wy.

220K1 0015 0068 1_6801_680

VARIS

- - C277

4 01(47

2210

0_ J 1239RISE SW101330K NORM PUR. 5ERV

SWITCH

8263L54,1*

- C25047 V207

6FQ7HOW OSC

TP20

8268390K R270

560KC251 8271

D203 12K

A,8 68

1--C252

C24400

.,222

R2;p7,3

1208

0,1209 2203 0 1238

C10313 2

350v

R283331

8284150K

C 2 710022

8112,7506VERT HOLD

3

9-5

C274,

R286 R290

122708238 GNO150

8 V P -P

15,750 'Is

13

9V P -P

3.58 ML

ioov160V P -P

15,750%

v703E1

147K R727 4.7K

R737 "67 1/2 6GH8A1/2 6GH8AKILLER t5OK

C 7d.13_

56 BURST AMP W`274-1-.73.

R701 S J C74512-11

I

120, 0 18 25V2

iv tTICI 2719 0

-101720R i33, IMEG

COLOR KILLER

R1343 3K

DL101

DELAY LINE

V208A I

1/26GF7A 8243 1

VE217,76482

0

OUT00

120K

C

46728:

R2893 3MEG 3

C267

1242

8291IK

1365v50, ISOV

1

2 210E5 2 7MEG 1-RI20TO 5102-2

235 2234 150

2 R118

0117, 3.4 MEGVERT LIN

508 WZGHT

223

405VC 103C FiOi

25,250441,1P FUSE

2 R1354,6Krt TINT CONT3 l Al 4.7 -

8136,120-

1510

R137,3906405V -or\ A.A.-

15-2

23IS I

R1304,250K

1102VERTICAL OUTPUT

TRANS

CII7.001 2KV 2

REO

ORR

BRIGHTNESS

PIN 7

BLR/WNT PIN 3ORG

Pm 6PM 5

EAR/GRI AN 1

PIN 4EAR/RED

YE

GRN/WNT

DRY/761

TO 5102

R127, 10F GAN

//cv,,8ERT

CENT

047

0726.01

12721

L5 -I3 R739, 10 MEGC

0104- R757

I J733 220K

I 2734

I

J735 D702 074014 I

R754 Cl74

680 0 t.L706 ,R57K55

C730

48

8.5V P -P

60%

OI7V P -P

15,750%

IS WWI CD

120V P -P 140V P -P

60% 15,750%

24

300V P -P

15,750%

e300V P -P

F5,750%

A

D

L70947uN

1.001

TRANS.

C723

Y701 153.58MC

XTAL

873I' I

R732 1C724

IJJ-35047K 2-10

AOSC.40,1

405V

C722

87382.7 MEG

2728

22

120181

L 712

V705126N7A

2ND VIDEO

2.28 2

j736 0 02730 .1731

CI1922

MED

LO

SWI02VIDEO PEAK

r

L.__

620UH

7 4L707618 2K

C743R7 K4922222W

J770

0704AI/2 6GH8A

358 MC OSC

C736 L

R743 L 704= 82 6 5

I

UN

476,I14 681.1.3

12

C734 C73501 - 12

9-79-8 IF1- 0,50V

9-6

CI260/40V

2

-C7T(.1),( .05

C121

0015

1( 4,

8139, 20CONTRAST

IINORIZ FRED. VIO

.0015 .01 1206 Oniz OUTPuT- C260 C261 E6A

L2086

C255 8275 R213 R107C262 R276390 686

'68080K 10 100

/ MEGSINE

AVE

).180e 2 7R274 R256f 27KR278

MEG I W

R262 R269390K 220K

249

C253820 R281

C2- 56 R279820 Z 33K

826,14, JJ 28

RV 202 690

02223 1221 Q 0 01220

(n, 9-48105 9-1 400V226N4.4.- *3.4043

8106, 356HORIZ HOLD

4. (?3f9-3

810847

C1041

R1092087)V

C106

130,64V

RII01.211

OW

RIII128

DI01

FOCUS RECT.

RII3 RI1566MEG 4.7 MEG

6K4v

1004 PIN TUBE114

5 PIN 9 OF"FOCUS" TO

FOCUS ADJTTIR05.6

7101TRANS

vIO23A3A

H V REC7C110 C,II

Iv; 46Kv

25KV

v103

CII5 6BK4B8I2 3 8I24 .01 SHUNT REG

S6 MEG 75 MEG 1.KV IIIIWSY.

RI25, 500K SPARK 1M26,IK8122 . v. ADJ. GAP

4 IW L10

S

9

D102BOOST RECT

01C108 1 L4

2 130K ti 0 o +130,2 5K

RII6100K

88

FC

R121,10HOR1Z

CENT

800V

405V

C112 1068

C113

052.24

S GUM

C1140335%

L102

5 608

L103NORIZEFFCOIL

V104

60W482 7 DAMPER

CII6

-122

v TO 5102 8

C105,.01I(

1.468

SPARK GAP

AA/250V 5005reo BOOST

RI28,150

WHr -rEL

r36- I

THERMIS. vERT5-"COUE COILS

-tq--S71HOR12. COILS

I 617-r$1.711 ,n

3KV 2*

DEFLECTION YOKE L104

R1295101 ISO

YOKESOCKET

P101YOKEPLUG

1100 COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN OJIBWAY BUILDING DULUTH MINNESOTA 55802

-GAF,' ilF-R815,60,3,10

TOP 8LLI5.100 HOR1Z L S

REIVWNTI,1E R813,120,2W

TOP RED-GRNHORIZ LINES

,r700

pIO2

CONVERG

PLUG

SI02

CONVERG.

SOCKET

R00160, 3wLET HORIZ131.0 Rso,

150,1w

C801,

C802.052

a R811,150,2*TOP RED-GRNVERT LINES

R808,60, 3v/BOO BLu

ORIZ LINES

BOT RED -GRN

VERT LINES

Re12, 500,3W807 RED-GRNHORIZ LINES

C80710, 6V

9136390

R81047 CR130ID

B

C

_ 4.1,/ ff1.7 ff-0/ G5N _ORR/ WHr

JUI614t;REV Ir'rr 'WPM -ft

06A

-},EH°R-, 7 oil,:

Wci,/lu7/1_

..78/00Z:w-i01.J H/GRN

CR801-- rf 4"

RED-GRN

15R08',34LrNESVER T -L803

BLU-HORHAP

R8022701*

L804T NORBLU

L801RT vERT L S

RED - GRN

100, lw,NRec40

18027 NoR

RED-GRN

R80600, 1

_J

SYMBOL DESCRIPTION

C

103A)

80µI 450vC103B 2µ1 350v electC103C 25µ125v(107,115 01µI 1 4kv *80-20% ceramic(106 130pf 6kv 20% N2200 ceramicC106109 130pf 2 5kv 10% N2200 ceramicC III 68pf 4kv 10% NI 500 ceramic(116- 22pf Ikv 20% N750 ceramic(117 1000pf 2kv 20% paperC125A 800 450v(1258 30µ1 450v elect

C125C I 20µf 450vC 1 25D 20µ1450vC126A 80µ1450vC1268 50µf 450v electC126C 20µ1250vC1260 50µ1 50vC216 - 3 15pf ceramic trimmer(232.233 - lOpf 500v -L-5% NPO ceramicC255 - 390pf 2kv 5% NI500 ceramicC262 - 680pf 500. 5". mica(707 33061 500v 5% mica

V 707A

V2 6GH8ACHROMA BANDPASS

L 710CHROMATAKE -OFFCOIL

.") 2

3723

7

C71I820

8762390

T 701CHROMA

9ANDPASS TRANS

C706.001

#7641.5 K

R765560

27011

AIRLINE C733 - 56061 500v 5% mica 045-008600PART NO R109 - 13K 7w 10% film 054-133710

RI10,111 - 1200114w 10% film 054 122410R113 - 66M 6kv 20% film . 057.000400

034.025800 8131,132 - 156 Sw 10% film 054-153510R141 -27K 7w 10% film .. 054.273710

837.103896 R151 2,5K lOw 10% WW 053-252110035 033300 R154 -- 1111K 20w 10% WW , .. . 053-142310035-043200 RI 26 - 15-K trimmer pot 055-055400886-680017 RT201 - thermistor 057-001200

10TCU-022 RV201 -- voltage dependent resistor 057.000200046-015500 RV202 - voltage dependent resistor 057-001600

RV203 - voltage dependent resistor 057-001300R706 -6800114w 10% film 054-682410

034-027000 L101,102- 5.6uh RC choke coil 111 021200L103 - horiz efficiency coil / 11-0362001104 -- deflection yoke assembly wicable and plug 027 0319001.105 - filter choke 032-002600

034-026000 1201 47 25MHz trop cod 109-0360001203,204 filament choke . I 1 1 0351001205 - 4 5MHz trap coil 109-034700

050-003500 1206.210.212 1.8µh choke cod 1 I 1 02100010TC-010 1207 - 36µh peoking coil ... 111-036900

886-391957 1208 - horiz osc coil 110-003800045-007300 1211 - 12µh choke coil III -036800047 007200 1213 3.9µ1,1Kike soil 111-036400

R1358 500 V7014COLOR' CONY

I V2 6GH8AL703"5 9

I5.6UH

4250 I

15-''j1

J 704 C702 11.7293

LI).,' ..`

L ' 5 _ _ i R702470

4717 0

1101/

C701,001

56K

T 7033 68 MC. OSC

TRANS

r -

3,74628.

IA704 8

1/2 6GH8ABLANKER

L1085 61.10 R75I

2206

265V

R750 R7521 5 MEG 6865:

C739C738 ISO

3710 371 0R

M4EIG1

1

L705, 3 9 Um

R744100,1WC733560

C729, 001

7

V7018L 701 "6 1/2 6GH8A R74062041-1 1208 !MEG

R -Y AMP

C70333

8709 S R718

6.2K, 8206R720

3716 6882651,

C709 C704C706,01 no 200 1

-3- 9-3(-R710

6211,1*

0702A1/2 6GH8A

R74570

C7i0 0717I MEG

91 -1-

c 756100

V70781/2 6GH8A

R713 G Y AMPISOK

0760390

v 70281/2 6GH8A

L702 8723 8-V AMP620UH 12016

,i071 0705'`33

2

\,71:7

C71 R 724

C7S9100

C714, 22-9(

8734 iR706 L70847K 68K 390U0

4W

R7536816

zw

8

R82T205

IW

0750

.047

1214 - 60µh peaking coilL2I5 - 82µh choke coil1.701,702 - 620µh toll1703,711 - 5.7µh codL704- 68µh coilL705 - 3.9µh coil1.706 - 27µh calL707 -- 620µ11 coilL708 - 390µh codL709 - 47µh cal17I0 - chrome take -oft coil1711- 120uh coil1801 R/G vert lines coil1.802 horiz lines coilL803 blue hour shape coil1804 blue horiz hoes tollTIOI horiz output ',former1102 vert output :formerT103 - oudio output :formerT104 power :formerTI05 .. focus :formerT201 - sod take -off :formerT202 -4.5MHz interstoge :formerT203 - 4 SMHz demndiiIntor vforrnerT204 -1st ply If input :former1205- 1st pia IF plate :former

r67I9 R74788 1MEG

2W

8

37281

8707I

6.80,3W 13W. 0LE3.2726 0,1E7 372

/40VTO VHFTUNER

/401, no

R1483 38,10W

24C(12V257_,20,4500 8149

18,3W51

3901030th ,12-7 80,45004r ;1,1._ 26511 C 1268

C 1250 S0,20,45011 450V

R151

CI26C .-ta 2 516,10W20,25002301'.

8152 v RI54686,48

9140 86GRN DRIVE

RMI2787W

2

Ant 6168L4 ORNE

81452506PIT

BIAS

1 30737

32

13715

105V

R712IMEG

C 749, .047

R711 871568K 1MEG2W

R769I MEG

L7443, u4r

R7268721688

2111'MEG

R746IK

3701

J703

370WVR722

18

Rg:L7g4

5G 101

SG 102

SGIO3

S104

9 -PINRECEPTI AL

10203040 5060711190

1 0 2 0 3040 50 60Yee 090ENII 01203014015e

1ISP105NR CEPTICAL

RED

GAN

06/

rEg. /ENV1217

re-L/Fifty

rfL/WO 2

051,1.4 16,209

1001.401258 1.9

30,4501

03680

TO VHFTUNER FIL

LIE OAUSSINGPLUG 8 SOCKET

S103 /N,1RED

&Of GAUSSiNG

I COILS

SW103ON -OFF, POWER SWITCH

7 PI. 101, VHF

o SECTION 1 .4'" CHANNEL ND

OCR RED :2-1 12-2RED &A'r -072:Tcari ® ®

C213

13247=.001

C208

5205 IC 21,1001

wl C2060207 .001 32481

L

RV 203 RT 2011

3245:

4

T104POWER TRANS

!'RED 8LII /SINT"'de 10iCIRCUITBREAKER

GRN/RE0

GRN

3

111-035000111.034900111.036700111.036500111.035400111-036400111.035200111.037000III 036600111-035300109-033800111.021400111-031800I 1 1 031 700111-031900111.031600033 011800033-013300031 009400033 012900111-032200109-034100109-034200109 034300109 034400109 034500

SIO6

12 -PINRECEPTICAL/V.V.\10203040 50 6070809100110120

T206 -2nd p.o If :formerT701 - chrome band-pass :formerT702 - burst amplifier :formerT703 -3 58MHz osc :formerR103 - AGC 50KR106- horiz hold 35KR112 - vert hold 750KR117-vert lin 3 4MR119 vert height 100KR121 - horiz centering 1011R125 high voltooe 500KR127 vert centering 1012R130A volume 1MR1306 brightness 250KR135A - tint 6KR135B -color 500KRI39 - contrast 12011R140 - green drive 6KRI42 -blue drive 6K .

RI43 - pix tube bias 250KR144 - blue screen adjust 1 5MR145 - green screen °Must 15MRI46 - red screen odiust I SMR153 color killer 1M8801,808,814.815 6012 3w WWR804,811 - 1501/ 2w WW

- NOTE- ----DENOTES DENOTES PINCONNECTOR NUMBER ON I

CONNFC TOR

5-3

SYMBOL INDICATESL L'L1E0 VECESt LC9E1NL.c

V 105

I9EXP22POT TUBE

4

WNT/RE D5 13

WNT/GRN

RI4EILU SCR.

C122001

3J LAca..1CI23

9145 I 5 MEGGRN SCR

R

"'03147

10 3 2 FIM10.51,

/250V BOOSTED BOOST"FOCUS TO RI1S

LIGHT12 5 12-6 12-9

® ®0 SW 104

VACATIONSWITCH

1.05 2.C125A80,4500

TL.C1261180, 4501/

/11551806 0105

14

81561508

7V103

0(11/Rf0

12-9 v701 V702 V703 V704 0705 V706 0707 -1

V101 V104

0705

4 S

C127

X

SRN

437061 F102

IFUSE WIRE

- - - J ORN/BLA'

El 201 Vzoz -V203 32* V204 0205 V206 0207 V21:11!

32 36

5 I 4

L

3 4 4 5

-

CPR.150 7r

`22MEG 12011 AC60 CYCLES

SECTION 2

TO WOTUNER

F IL

ACINTERLOCK

41?0:""

1.2 -

25711(RED1

1A0 1I -ISOCKETSPARK OAP

NOTES:I ALL RESISTORS ARE I/O WATT, UNLESS OTHERWISE

NOTED

2 CAPACITANCE. VALUES GREATER THAN 1.0 ARE IN TAWVALUES LESS THAN I.0 ARE IN MFD

3 DAMON° INDICATES COMPONENT IS NOT PART OF BOARDASSEMBLY.

ALL ELECTROLYTIC CAPACITANCE VALUES ARE IN 880

S VOLTAGES ARE TAKEN WITH V TVIA NC SIGNAL INPUTFROM POINTS INDICATED TO DOSS, GROUND

6 BALLOONS®, 0,ETC., DE NOTES POINTSOF OBSERVATION OF THE WAVEFORMS

SIO5TLNER 6 CRONYPANEL comma.

tir.corrsais

3

2168ANCC8111)10

AEU

ST PIKETRANS

109-034600109-035700109-033700109-035600055-058200055-057100055-057000055-058100055-057500056-039100055-036500056-037700

AIRLINEColor TV Model GHJ-8247A,57A

R805,813 - 12012 2w WW 056-047200056-046700

055-058400 0101 -diode focus rectifier 004-003200D102 - diode boost rectifier 004-003100

055-055600 chrorna board 073-036000055-055500 CB101 -circuit breaker 3amp 009-002500055-057600 (P8101,102 - couplate 2.2M/1000/S6 134-039400055-057700 01101 -delay line 111-036100

.055-057300 F101 - fuse .4omp slo-blo 099-002800

.055-058000 5G101,102,103 - spark gop 140-000300055-057900 SW 102 - switch video peaking 146-007800055-057800 SW103 - switch ON/Off power . 146-010500

.055-057400056-046800

tuner VHF

) see tuner ports list006-018600

056-047300 tuner UHF 006-018901

CHASSIS LAYOUT

R8I - 50012 3w WW

CIARROW DENOTES KEYWAY LOCATOR POSITOSII

Marx uisliv,7206

W ,.. FPLATE TRANS. V20NYE be Pa TRANS --, SOLND

Ai i---..,''6.106 6.I06 01 LOOS 646.1.-_,.., s..._."

4 SMC Ws \ _,/1ST F /9,MI PLATE r, \

L'27);TRANS ErGANIA 46/141,4

IOC TRAP ".,. Ai s..,ce,,,..4725

0207 7"." ARECEPTACLE VERT OSC 101120sc SF07 ®

8 OUTPUTC724

-_,./NYC OSC l' 70

VI' --.46 .. CRITT11. VI04Ur ,---",---- 0703 DOWER

a ED 7Th 41,\ 66stea BURST AMP 8

T703 6049A, ,_.,,, lour R

3 ra sc - - - ' .112521 Oi&13480PASS ,--,

8 BLANKER, 424,,, TRANS

°''--- "M41261,V

6f tut "4' sior 1.41 aro IMO VREOV705

,,,L., 6611811 Tomo(' `,....-/ OIROIAA

0701 '...._..1 8, ARP V707 31:"X11E16008 cwicw.

C

R -T MCP 11/310MSS ,_ _.64-00

U 1111 1-1 L-1 W 1 ji ii w

tioconsirser ve/F7ADE TE

5106

PONEMPLTTRANS

17

V706

CKI038:15AC

C103C

VOLTAGE CHART

9°4TTR5WC76S ,711N6

02

02tC74205111 CONVE MGM9"CCET

TRMIS.5:07C.1.1:T

SOCKET

J1.105

'FILTER CHOKE

---- - -014 VOLT

REGULATOR

OO

0214 VOLT

RECTE ER

;.31/34

PIN

MBE FUNCTION 1 2 3 4

VI6HA5

R -F

Aii.plif;0 0 0 634C 170 0 0

V261187

VHF Osc.Mixer

0 -2.4 0 0 6.5AC 130 130 131 0

11101

6JE6AHorizontalOutput

130 -55 0 0 6.3AC -55 130 35 0

V102 High Voltage3A3A Rectifier 25KV 25KV

V103 Shunt6138413 Rrgulatot

400 390

V1046Dwaes D"'`` 400 6.300 0 400 IX)NOT

REMEASUV201

6195Sound IFAmplifier

1.5 0 1.5 0 6.3AC N.C. 95 95 u

V2026HZ6

SoundDemodulator

0 1.2 6.3AC 0 135 115 0.5

V2031

1st Pi: IF6JD6 1 Amplifier

0.6 0 0.6 0 6.3AC N.C. 95 95 0

112041 2nd PIT IF

6JC6 Amplifier1.5 0 1.5 0 6.3AC N.C. 165 165 0

V205 I.. Vid Sync.6GH8A AGC, Chroma

140 -2.0 140 0 6.3AC 260 0 8.5 6.0

112066G1i8A

AGC & SyncSeparator

85 70 250 6.3AC 0 -10 90 0 -20

11207

6FQ7HorizontalOscillator 25 0.3 1.0 6.3AC 0 260 -115 0 0

V2086CF7A

Vert. Osc.& Output

0 60 70 0 6.3AC 260 0 8.5 6.0

V7016GH8A

"X" Denrod. &R -Y Amp. 125 -2.8 2.8 6.3AC 0 250 0 12 10

5/7026C118A

"Z" Demod. &B -Y Amp.

125 -2.8 2.8 6.3AC 0 250 0 12 10

17036G1-1BA

Burst Amp. &Color Killer

a-5.5-12

.2.44

255 6.3AC 0 400 55 0 -2

V7046(1313A

3.58 Mc Osc.& Blanker

120 6.0 150 6.3AC 0 215 0 3.0 -80

V70512GN7 A

2nd VideoAmplifier

0I.0-8.0 0 63AC. 6.3AC 0

290" 360

85165 0

V7066E3Q5

AudioOutput

N.C. 0 6.5 6.3AC 0 N.C. 230 N.C. 240

V7076G}i8A

Chiang Band-P'5' SC G-YAmplifier

125.3.0-II 160 6.3AC 0 255

3.02 .0

12 10

N. C. No Connrtion MEASURING CONDITIONSDC voltages measurd with VTVIA placed between point measured and chassis ground.Channel selector st to active channel. Unleiks otherwise noted, brightness and contrast controls se for normal picture on screen.Denotes readings token with brightnss control at maximum 'motion (fully CY).

Disnote readings taken with brightnss control minimum rotation (fully CW).Disnotes reeding* token with color signal.

voltag 'input set or 120 volt. AC.CAUTION: Exercise xer4414 car to avoid shock hayard. Dangerous pulsed high voltages ore prissent at VI01, 0102, 0103 and VI04.

Eercis Neni cam when measuring near these tubes.

COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN OJIBWAY BUILDING. DULUTH. MINNESOTA 55802

1101CANADIANGENERALELECTRIC

TV Chassis M649

AUGUST 1967

FiL +275V +135VB+3 8+1

1501111ECT0S ION11086810 SETS

CORRECTION FOR WEARER SE TS

ICY

40v60^,

Lfil 053 0114,111112 10TEZ

1,000 - I.000.000

CARACITR

YON 774441 I - manCA,ACI LESS DWI I -RESIST ARE 4 VATT

I

ELECTRONIC 1- /17=L7TECHNICIAN /

COMPLETE MANUFACTURERS' CIRCUIT DIAGRAMSAND TECHNICAL INFORMATION FOR 6 NEW SETS

7170676 79,65 6.6,77.eu e Lts,

MODEL CAT.IITHIR

DRANIND 9401306cOD[ HOOLL UT.

TIMORDRA91310

VENDORCODE

22-222 67653 17769139 7477. 33765 67653 177691372 'R7"

23-24 87653 17709119 -Cr 35763 67655 8610660

23-25 8765) 17769139 -1677

157643576412

6765587657

06106806610601 I oler

07656 46%4471-2 IMF,31465 87655 561666031767)17670

P765507657

86106800610691 II4T7 (VTR)

36176236764

8765567655

6611366086106210 '61-

57656 40104471-2 I1101 3611740 6765707656

861136814904471-2

(0937)11071

32761 07655 0610680327610 87657 136106121 -47. (.79 36766 67655 86113680

87656 49104471-2 (TAR)36767 01655 8610680

32764 87655 861068032765 67655 0610680 39762 07655 06106330327766 07655 06106130 397620 87657

67656061068140144471J2

IVHF)(LIHTI

V36926311-2

11200217

2

6151

108

111511

2204 C.52

1. ILL 6101.1461 31631.513(415

r01$10IPE:1 411"40;I(00545515 Mum), 5(15 60-0E16E4 COW6OLS SE1 01251106541. OPERATICM.

2.

. 11771 iEimicvolTAGE

54 11 74 1MED

5535A4CILL 15EriNV0M01ST32013 1 0N T3(,0FLRh-106 10011 9611044[0 TO A 07440-MEL 5(114 PO SIONAL_AN 71E11001614 1(0(0(13Anc5TED.

04-110441. 90A760E5 AMS

WAIt/egii:triViM 49°10.1FRE 510141 PIRIOUCI,L -I.to -2 904.75_1g AT Alf(no( 31.6048 03.5110A 60.1521r08 84.5)31.14 ACC.

ALL 00W9 C051001.5 40.8.61E0Aryl KAUAI. OPERATICS.

6 140420 1168260160.5 crwe

+(33VB4 1

0197v 2

2 001060064

7290

mooJOY

+275V.8+3

4152

120

V488213250.

0100

IiCI40

'600 1'09,

VARIES WITH CONTROL SETTING.

902 SCOPE ST5CE0 AT F 6E91 19T217

9/2 SCOWL 576CE0 AT F 14:51. FREQ.

v.5Ea 04

6401

025)

30

4702

:Sr "4"1"E.41 9.62005,

A

40631000,

9.5 ';::"5501-7

1,5800

RC .66

I 6.664106

+2 VB+3

5365228

I . F. OUT __

A.G. C

R.F. A

TUBE

6ES8U. H. F.

By SVII TC

R27 0N...°INPU.

U.

F.ONL/ T

1)530E0 0(7'.0000 55E171817

pd

+135V

V68.2 6111.14C1100E6

0,63

053 1.79

016.

+276 v

1120)4717IS

7,5)

0225

K.

52;:2

%A.

HO

C2IF

-0205SOO

ISO

_B. F.TEST POINT

R. F. El+

TR IIAIER 200V.

058

,

ITTRi6T7%051470

- 60470

6683900

VIOA1,7 UT/vf. 9T 05,

5202

4T o

1,2- C203

.0039

041060200v

V6A

00E0 AMP

I . F.TUNING

(--HEATER

13+ 1350.

1406

6205

6114

C169

c470ADA

+135V 3.66 V8+1 +135V

8+Infoto

8+3 +275V

MIXERTR IIAIER

ACCESS TOCONVERTER GRID

7154600.012 TAKE OFF

4 5 MC 3016.5

CONVERTERTUBE

6GJ7

05C ADJUST

0210511

Iiv820

0001

0201

111E6

0160C.112

11221 3400

4 5W022

R/006008

VI2AN/3 IMO00,2 My

VI2A

01101 1,107 7,.. 7 5404 sow 91.1,0.0

m0DEAS '9,- 034

C5015000

C255

'cx'° 1.c25.820

orls3LSO -/V

52015001

-Cr256

1.20C4;,.!1,1,7

+8+39

T50,06110 0(77 -

VI 2 BIn 8540

50 0)7 he

926415

62i916

I c.2.1- KV

6201 C270AA.

4700 470

6110

e R2697504

C2011

0,c;'

"

400)0

522Tn401258

X96CON r

4169

SNOBuz 8691

628TOUTPAT0206

015

4000075v

(161.2751.1

.015(08 1

e

V16PICTURE TUBE

81141474

4.62

0)16i4011

206,707.96,GHTNE55

5020i56078 Goo

0178II. 1. Ny

.2(

4711

B4 150057 0.4 500065215

0047ofOR ,0611

1201

1 253

MITE

6262 +2750 VI3270 8+3 60068

.70362 07.01001

926'5I'M4700

re

725)

orsETS

4771 R4415o5.. ,

i08(, 6

1

,05. %,?.;

V 7 .30RA 74 II.--.

I ®91 7.7.-. Amp

;Z. 1 U ITi

I

JUMPERON MODELS161136507 VT

302

+)35V13+4

V8A2.3 6,1481217,0 O(T

C50102)03

6005 25vOLLIE a 59

C300A

2204

#306

2"2

01071- 2000

0280-11-7410474006

421111

I/645

3

V)4MST

RE:T

1253

(712E5051

1. 252

881/5V o WS? rural *134:41; v9

6C7.75AUDi0 OUTPUT

eII

00 3l.50901?'

932680,1

z3,1

RIR TONIBOOK

OBS

=.011)02 9600

OM OW BM

407E-0507.0)0655)07 50514Itt USEC ft 23'5E15 00t9

'00 Met 65242m.017'

R5.54700

VPTX'13+13 58+1

026'2200

V15-

G PEP

III A

7302

III

ar .0

TUBE 9 ADJUSTMENT LOCATIONSM649

74"

''2t 08+275V600 8+325

ti

111116

275V8+3 R303 - RC CirCilit de -emphasis network

F251 -fuse 0.375 amp slo-blo R4962F401 - fuse 3.5 amp bayonet type R5340L402 - reactor filter 666I IR204 control vert size 1.5K R6674R208 -control vert lin 4.5M R68869257 - control bora hold IM R42560270 -control AGC 2K 97544C150 -ceramic 22pf 5% 500v NPO R4625

4.61C264 ceramic 120pf 10% 4kv IC R6614C202 -ceramic 800pf 20% 1500kv 94631(405,002 ceramic I000pf GMV 20000 R4935

an ""a"aal "a C203 - paper 00390 10% 1000v1 MID 4 II, ***** SITb .

7.10 C3 i 4 - ceramic .01323 GMV 10000 R3034C152 - mylor .22,41 20% 2000

94618

R6386C313 - electrolytic 1100µf 150v R4637C406 - elect 1250 200v R604704016,6 - 10014l 1200 120µl 2000 66616C40IC.D - 100W 150v 100µf 125vR177 control bright 200K (Model 31765) 67I76R173 -control contrast 25K (Model 311651 R7180R219 -CODOCK Vert hold IM (Model 31T65) 671 78R311 control tone 300K (Model 311651 R7658R306 control vol 2M (Model 31165) 671 74

TO CAP

OF VI3

TO

L252

TO

YOKE

TO PINS287

OF VI4

TO PINTOF VI7 R27I

(270

T251 WIRING

L255WIDTH COIL

TO 1251

TO PIN 6OF CRT

GICIOND

CANADIAN G -ESYMBOL DESCRIPTION PART NO.

1152 -coil IF R55651151 coil 1st If grid R4655LI57 - coil choke IOLA 20% R64021.158 - coil choke 7130 10% R4650160 - coil choke 4700 7% R6733L161 -. coil choke 2400 7.0 95328L251 -coil horn stabilizing 666I8L255 - coil width R66711302 - :former audio output R6044T251 - 'former hone MOW R76521401 - xformer power R75701151 'dormer 1st IF plate 85329T152 - kformer Ind IF plate R6272T153 video det ass,/ R61511154 - of OrMer audio take -off and trap . 1158091201 -'former Vert output 666I21301 -'former ratio det R4955L201 - yoke deflection R6620Y151 - diode R18891401,1402 - diode silicon rest R6048R269 - therMiStOr 750K R6897RC166 RC 1.100 4701147014f R4917RC304 - RC and 221/800/4) . 94648C303A,B.0 - 95318

1 101 COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN OJIBWAY BUILDING. DULUTH. MINNESOTA 55802

1102

0 IMF ANTENNA300 CAN

UHF TUNER

0 82 UHF OUTPUT

eICI

VC,

12

UHF MI X

_de c:Di IS750zv

C37

irt--/vsne-ez-enzse----R .72000 R,e 8800

I IIC34500

IC 3

UHF OSCR

2 SC3 I 3

I - 5

Cm22t019

I-TC4

TUBE PLACEMENT CHART

SERVICING IN THE FIELD

SAFETY GLASSFor picture tube and safety glass cleaning, it is

necessary to remove the chassis. (See Disassembl)Instructions.)

FUSE

-A -T Amp. fuse is used for L.V. power supplyand filament protection (See "Tube PlacementChart" for location.)

VHF OSCILLATOR ADJUSTMENTSet Fine Tuning control at Center of its ronge andadjust oscillator slug (one tor each channel) forbest sound and picture.

AGCACC may be varied 'cry means of on AGC control(See "Tube Placement Chart" for location.)

FOCUSThus may be varied Ly connecting the leadfrom resistor R-166 from pin 4 of picture tube tovarious voltage points. (For location see "TubePlacement Chart.)

CENTERINGCentering is accomplished by two magnetic ringslocated on rear cover of yoke.

HORIZONTAL LINEARITYHorizontal linearity can be adjusted by turning thedisc magnets located on each side of the yoke.

HORIZONTAL OSCILLATOR FIELD ADJUSTMENTCoarse adjustment of the horizontal hold is accom-plished by the proper setting of the Horizontal StoI izer coil and Horizontal Range control. (See "TubePlacement Chart", for location )

L_

TUNING

CORONADO

SYMBOL DESCRIPTION PART NO

01- video det IN6002 - silicon rectifier (155581 T E 1024C1201- AT output T VI201202. vert output 1 W27T203 - horiz output (flyback) 1176/1-331204 - deflection yoke 1D41A1102 -heater choke T 506L103 -4725MH2 trap 1 515251.104 - video If input T-51814LIOS- video trap T.S15261106- first video T510221107 -video del T-51023L108 -filter coil 1 170301109 -filter coil 1 170301110- snd take -off and trap T520091111 -peaking coil (270µh) 1.12005L112 - peaking roil (4130zah) 1.120061113 -peaking coil (220sch Sk) 1.120041114-4 5MHz snd IF 7.52010L115 quad (520111116 horit stabilizer 1-A2S

VHF Ant WWI0 0

RODANTENNA

C 2C. 1000

_LI 50V -AC

VHF Antenna

VHF TUNER 0--.-0 TP.A

/ UHF IN

-0 U6+

1PrKo2

T. Tb 659USP

V Hs V.H.

IF OUT() -_a

VHF RF AMP

V 301(5VHF OSC

V z 6CG8-A

B.

145+

-0 8

) UHFOUT

UHF TUNER1.1 i 025US

UHF Antenna

r3CsK5

AGC

VHF TUNER

6CGB.A

3 4 5 0

C.9,11000

13E07

1117- RI choke1118- combination coil1202 line filter1203 - filter chokeVR101- -AGC 100KVR102 - height IMVR103- vent hn 300KVR104 - Hon/ hold 45KVR105 horn ronge 100KVR204- yell hold 1MVR21 I - contrast 30KVR212 - brightness 100K+11221 vol on off 500KR114 7K 3wR200 - I211 2vrR221 - 680112wR241 - 312 Sw(106- 0 22pf @ ISOwvCI24 SOsrl @ 6wvCIS1 -3µf@300wvC 170 1000sdpoly @ 500wvC244 250 200 30s2I @ 200wv

VHF tunerUHF tune

SOUND IF AMPVine 12 IOJY8

R

C103

L.51 I a

01R 02

330K

C

TP.E 1000

LOOP ANTENNA

UHF Antenna

128 VP4

11,412

17f3F i

5 4

33GY7 17./28

12

12

47K

R107 56

v7C104

.20 roLioa

OTP 0

C .oil C.os

"1 1500(

3 88V

L .04

1.1071.17069

T.108TB28A

1.0003111.0003211.G00331

TG0034T-000391-020241-02023T.020251-02017

RC 607RC -720RW.27

9.13TCC-010

CE 174.2300(13

690.147T TB659USP20

1 110251.1S

SOUND MTVI I.. I1BFI

C,.3 1000

ELECTRONIC A-7 /--TW=7 AiCa7KTECHNICIAN /


CAUTIONONE SIDE OF AC LINE CONNECTED TO CHASSIS

CORONADOTV Model TV21 9367A

AUGUST 1967

TUBES

POWER SUPPLY

TUNING RANGE

VHF - Twelve, UHF - One Transistor

110-120 Volts AC, 60 Cycles RATING 101 Watts 117 Volts AC

Channels 2 thru 13 VHF, 14 thru 83 UHF, Video IF 45.75 MC, Sound IF 41.25 MC (Intercarrier)

R 33 5300

c

KR 22.VOLUME 500K

C so5000

TP-H

TP I.

C esTO 04MFD

= Rios C.2. L ,o100K 50

SOUND OUTPUTV1048 '2 I 7BFI I

I9C

50

160/

r7gVCs.3MFD

150 300WVt

1ST IFViol 4EH7

14,;.7f 143V

9z

0 27VTpa 0 56V

g °

IO2

If ,55601(

R.".I MEG

3

R 0322

rII -L os C ,,01

20001

870y

AAPR

10K

0

.2

15000

2ND IF AMPV102 4EJ7

L ios

IJ

II

VIDEO DETDi IN60

,z050

C

51

R2226 88

AU.68029

Tao.

-tC ,A4r30MFD2009 V

Bo

:60VIDEO AMP!V i 03A I 0.1Y8

55V

100145V 8..7 -

L

O TP)-Fa

C zs

C 2.

14 7K10>=1E8 =Zviro

R oe

8

27

I001

R .233K

: 30

23

ISO

CONTRAST

R2,821(

VR2 30K

C2,7.

C 290 / MFD

R220K

AGC

tti 8810VI 05A

.1 4V

VR.o. 100KAGC

8810

12

104.18

4EH7

I 12 T 4 5

TT oe 100011

4 5

L ,o, 4E47

tRioC.091000 4 5

C

11000

AC 60 120V

;MEG

R .218K

57V

R .43

C s 1

471(R.46331(

C 62

-1000

6

I I 6V

R 7821(

C ,63

11..3228

500 -

C.6.-5000'

se470(

V

1'7=56

3

0 3V 2

II

MEG

C.63100

SEPV1058

8810

5347K

52681(

ic,

c,..,550VERT OSC & OUTPUT V i06 17J28

60 331( 1- -.0 C . .173-1_11---A RWAN--------0-1

34V i.is 0 04MFD 135V0 11 56 0 022MFD I - I5V

3 9MEG C0 033 330

R ts3 iI

,se1(2/(

I

C 171_100

67V

VRIMEG

BH

HEIGHT

C os

1*

R 4000C .70

68N p.ws

R.,,1001( R

22K 17,

IMEG

XERT HOLD

VR .03300K

VR204IMEG

R4 7K

R .6.470

147V

VERT LIN

1 202

SPEAKER

42 VC

EAR PHONE JACKTPT 121 ONLY.

R .45K

C301000

PICTURE TUBE

V 202

I 1 2AVP4

2 3TP G

VRWOK

O 4.7.7.W4

4...,76FliGHTNESS7

FOCUS

4

H V

81f1 Cu 470K

6-RN SR

4'6 81(I F-410

c

0051

-C

r°47

C 74

0047}Rt 681(

-0TFLECTION YOKE1204

C es

0 003R. T. 11.7. HOP PHASEI°C: 68(:1( DET viosc

ma9 R 7s 1,i 8810680K

10

C

-0 6V

20

002I 1000

rtoR

151(7

0 43VNJrF1.ite

-R,7e ;

IMEG 82K TP -KC

R,rio11,"5000T C 46 2208

0 051

LINE FILTER

C24.I 0 I MFD

7 7

112 SILICON RECTIFIER 9, FILTER CHOKE

3 5w D2 i L203

ON OFF 2A +c

+SWITCH FUSE ufr--1

"` C aail

1000I II- - 1250MFD

20C4AFtij-

C 142

Cu.' 0 001

Rn9 471(

NOR OSCV107 8FQ7

C .50

2.

105V

117V

R e. 3 5V1K R Sr- 47K

IC 690 001

7 - 7 5V

VR .os8 50K

VR o.451(

MOP HOLD

C .95000

I

i

R

271(

C 50

1500

HOR OUTPUTV I06.4 33GY7

C P92 22K 1 435V15

9 10

R so av

150

.8,IMEG

Boost -v.-. loo' 1°°K

350V

T 203HV RECTV201 C

0 068

- I 32V§

Tee

R23436

15.3

O

H V

HOR

0

R23351(

--Q

-0- DAMPER

V 1066r -

C0on

0.41

VERT

C 2320 068

0(.1yu

C23.00

500

1123,500

1102 COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN OJIBWAY BUILDING. DULUTH, MINNESOTA 5 5 802

1103MAGNAVOXColor TV Chassis1920 Series

AUGUST 1967

SYMBOL DESCRIPTION

ELECTRONIC i7 rirVA=L/1AiTECHNICIAN


COLOR TELEVISION CHASSISSPECIFICATIONS

Power Source RatingMAGNAVOX

PART NO

C119 - ceramic .01 Al 1400v (w/spark gap)C130 - elect 20µf 450v 20/20scf 350v 270023.42(130 - elect 20taf 450v 20sif 350v 270023-43C2I 9 - ceromic 'Oaf 5% (NPO) 250508-1005C527 - ceramic 39061 5% 1500v (NI 500) 250236.63C528 - paper 01W 10% 400. (special) 250484.1C564 - elect Spot 25v 270082-603C735 - silver mica 270pf 5%C760 - mica 200pf 5%C771 - ceramic .01µ1 1000vR102 -1.1K 18w (WW) 2400884R106 -4 3K 5w (gloss) 230150.533R112 -15K 7w (glass) 230150.746RI13 - 1.8K 2w (gloss) 230160-65R114 - 22011 3w (glass) 230150-326R117- 66M 20% (6kv breakdown) 230161-1R128 - 3.3K 3w (gloss) 230150-330R119 - 1.811 3w (glass) 230150-324RI45 - 2.2K 3w (glass) 230150.330R160 -82011 lOw (WW) 240082.71R161 - 91011 5w (gloss) 2301 50-51 7RI 62 - 18K 4w (glass) 230150-448R206A,B -1SOK (matched within 2%)8617 - 5.6K 4w 230150-436R759A,B - 1M (matched within 2%)R780 - 27K 2w (gloss) 230160-79R792 - 2701) 3w (gloss) 230150-304R794 - 27K 2w (gloss) 230160.79R108 -45K horiz hold (see note) 220146-69R109 - 750K vert hold 220146-50R120 - 500K H.V. Adjust 220189-4R126 - 1011 2w vert centering 220181.10I31 - 1M color killer 220208-34RI33 - 60011 contrast 220146-29RI34 - 3M tone .220146-26RI36 - SOK AGC 220208.33RI38 - 1001) sharpness 220146-62R164 - 2 5K CRT bias 220181-118201 - 10K °di snd rei 220182-IR215- 75011 snd rejection 220166.4R401 - 1M off on vol UM chartR402 - 50011 color see chartR404 - 250K bright see chart

C406- 5.2 to 67pf hue see chart

12604 - 6K green drive 2201 66-1 5

R608 -3.4M yen lin 220166-1906I 1 - 1.5M blue screen 220166-17R804 - 1201,1 RIG Master tilt (horiz) 220167-6R8I3 -301112/0 differential tilt (vert) 220167-4R814 - 6011 RIG master tilt (ved) 220167-5RY101 - degaussing relay 160326-6TD101 -delay 360949-SVOR501- voristor 230167-5VDR701 - varistor 230175-2RV701 - therthistor 230170-2

circuit breaker 180723.2VHF tuner see chartUHF tuner see chart

300238-1361197-1361240-3320317-2320130-3

361154-1360951 Tuning Range360951-6360951-5360952-2 Antenna Input Impedance361192 I361094.2 IF Frequencies361198 I320124-4360676-5361022-3320232-3360676 7361135 1361250-I360852 5360953-2 Audio System (TV only)

TIOI - power *formerT102 - H.V. *formerT103 -focus *formerT104 - vert output *formerTIO5 - audio output *former7106 - pin cushion *formerT201 - video IF input *formerT202 - 1st video IF *former1203 - 2nd video IF *former1204 - 3rd video IF *former & 41.25MHz trapT701 - bandpass *formerT702- burst *formerT703 - 3.58MHz osc *former1101 - reactance choke1103 -5.6zzh choke1104 - horiz efficiency coilL109 -reactance choke (Int audio version)1110 - 5.6mh chokeL111 - pin cushiciAing phasing coilL112 - line filter1203 - I 77MHz tweet coil1206 -4.5MHz trapL208- 8.2µh cod 360677-11 Output Impedance1210 620z.th peaking coil 361043.31501 -horiz osc & sinc wove coil 360960-3 Power Output (Maximum)1701 - snd take off coil 360845-21702 -snd IF coil 360846-3003 - quad coil 360847-21707 - 150ph peaking coil 360853.51713 - 620ph peaking coil 360853-111717 - chrorno toke-off coil 360959-41802 -RIG differential amplitude coil 361092-31804 - horiz blue tilt coil 361188-11.805 -- blue master amplitude coil 361092-S

deflection yoke 361290-102(105 elect 1600 250v 80of 450v 270071-6C106 - elect 160µf 250v 270071.3C107 - elect 80/30500f 450v 270071.7C113 - ceramic 68pf 10% 4000v (N1500) 250475-24C118 - ceramic 130pf 6000v (N2200) 250475.11

250562-1

FrequencyVoltageWattage

Video IFSound IFIntercarrier IFColor Sub -Carrier (Nominal)

304C -(70101

000M04

ENO aid

r

I LLLLL OC

60 cycles117 volts

330 watts

Channels 2-83

Balanced 300 ohms

45. 75MC41. 25MC

4. 5MC42. 17MC

3.2 ohms2.5 watts

ON CHROMA BOARD

NON -REMOTEAC 01,10(17

0

TO 170701-414 cacao.,,,ON 0.01,14

BOARD

StO

uoxzoo

MON

0.0

104ON -OFF

INTL ERLOCK J

RN

OR

Ar

AF 70 wooeMs

ca

0

0404

10%

.0527Kin%

NOT uSE 0 ON SOME MOD, 5

V901611411

L90i

ROOS270 1000

% coos

WO5%

R90220

tO%

coos1000

TOW POINT

(2.

C907

(NO5%

RIOS0K

1/110090 20%

RIO/70

1/40FOY

ISO

950

R10015ii

zox

0

G120 TO220

C1105

:41k L902 L9035% r r

C901112tufo s%

C90450

L

C9011/NPO5%

.7?1'i001,10%

"Zri0IY/0%

.C140220

Cf..

090

i.%OS

A.FC.BOARD

J

PRESETDUCAT (1*ON 700.10

004

0 C

SHOT

1111015

CN1 05.07

22 JArc rural

WE NOTE Si

TO IT ON 00004 110.0N1OV

RA 4050IA IOV79 1401/VA 4170

NOS NOT USEDCliff 70. G720CM, C731

11104,0751101174Ru NM11723,11724.170R7111, 1110,1177i1041,071115,11/91

SOUNDTAKE -Orr

TRANI

ov

070111AUG

SOUND IC

0701:Si,

W

iWO

i-LOLt. p_ _ - -I -9,,,2-, C102

LAST NOS USEDC/7, 7703RT0 7101V7i2 CR /011.7111 71.1.

TO 10

VIOE0 If BDPIN Cur ROCI

RrITo TACERI

Bit11/4.SOK

OC

*2 TOO

10%

OV

700

c;g7,"3

002 004 0/0 OTOT

4

Rlif224(0

C71

L2,3

,,,,,,;VHF

p5-151 TUNER

Ov 4055c,c. SOURCE SOuRGE...

NIOWD2500 LP

960

C1054111011FD210v

0402

SR.201

Nx

ON CNRONBOARD

ALTERNATE

C101047

I 4.2_ -0 n

uSE0 00 NON -REMOTEUNiTS r,75-1

70-LK

INTERLOCK11101

224[0

510

L109

_I CM000

0/10717T O 111011011

RE0-111.

7102

1

TO AKON CORD.

90400

r

IVO

C

9WO

450v

C107130WD4500

I C20,

I 2114NPO

T20,viDEO r

1NPuT TRANS

1' 11036

violLIM01040 IF

5

1101IOK

ACHACENTINBOUND E7

L20411250AC

erzE Rios

C205.COO

C205000

720207 v040 IF

TRANS

1700

i700

RantTRANS

TO AGC PULSE71

V7034SOHN

ARC

v

4:040630

00 VIDEO IF

3 EivOR

6V

5%

112011

5%4/

: 0 9

3

C"Q"75

110V

5%

210

aet

990

2,00

,C10 0: 0,20V "M°110

C210

f*-iC2011

7.02 (PINTED. 4, 0L202 I

WOR

too*0007

,e0.,4000 Ciu

000

0

C2061000 .

in:1020000

C504,O 00

150

AR20410500

0990SOURCE

.70vSOURCE

1,00Noci

%C,059 Ri90 Qr

Mg

1400

Silos15500

O0

INTERLOCK

041ao

RN

200vSOURCE

1400SOURCE

!ILK -r/NT

3 WAY AC CIRCUIT-

AOc --70 04400.4 20 POD.3

-4TO C.O. BO PIN

O 1012 WO

_

r

SYNC

90500

051410

10515

990

NPO

10211 1152

1900 5100

510 ma120

COOS

SR104

050$001(

ICS011

0525too'

C553,1.

Xv

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7101WO v0E0 ri

TRANS

02410

Rita5500

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2200

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4403bin

3R0 V1040 II

-tv

12031RIO

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5%

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1.509iw

111

51100

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954

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SinWWI MC

NSW

stet/

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TONS

Rail8520

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io5%ro .

C214540

Ni500

7204360 VIDEO 1

ni TRANS I

PEN100

C

TO 4200,

0520

0042

85214100

4000060

VEST OUTP31

8521000

85192.z 11E0

OR 906601614

cns

2000r7500VERT HOLD

04 TO 00(0 CONTROLSilo. 60300

43034 V5011111 471SPOT VO? FR 0

OC CONY ROM 010 5

220 11150

050

81911000

ely

0.i0

C529,1.1-600SPEC "07% 0513

10990E

C527390

10500iSKL, fC529

6005%

WS*270

05300004000

5-

C522. C52327 920

N750

8530PS541500

R6160Kin%

R53/

20

--I

007 RIOS220 455 El Its

NIWZONTAL NOLO

Is

RCRM

R6841015%

0501

00015

8122

eC77: .5

002

TO RS

410415.140

MORIZ OUTPUTRIO100 2,

5501 I

150

P N

r _TO .740 C05700L BOARD -3

11.4. SAP., 07 1.401L0

2200300

T 02 EiKvMO

t CIN

Nov

8524aOK

C552*1000

DEFLECTOR BOARD

131(8112its70,

Co/047

too

11111

ISCO210

TRANS

.p

5100 PuLBE

400 PULL

1.50

7041250ro013

H

0

P

--4 TO 7101 PIN 10 (CONvEROENGE so PIN BO)

1000

I CEO -BL

ALON CNRONA

BOARD

3 WAY AC CIRCUIT

3V P -P

V204.2

45V P- P

JunctionR759& 6 CR702A

TO J101 PIN (CO. NNNNN GE 617 NI

880V P -P

V703-6

1103 COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN OJIBWAY BUILDING. DULUTH. MINNESOTA 5 58 02

T920-CbltETERNAL AUDIO

01 LTos ITT0AuU4,7..797

I

v102SOTS

10USI0 DE 600

00

,

Iv

0703 C7071163 01 00%

TOO

000

704

17050005

17115500

810112K

es:s ALL OTHER ENTERNAL AUDIO

1

122

11797CM0 510K :70t'"

oT,G 3,90 7SUlt 11795330 .,«©1 020

0712

Ov 1705--7

C7011,.'CnlI

5%

01 -

C710 + .10702 . 1701 r" - .1

1005 , "", --

MOO ' -- -F.'..C715

L704

0%

C724 C7252000 ISO

111151/25

32,4270

1720120[

312970K

R750 71/10

111091120.

-VA

010020E

V V

C7.71

TT

)5*ONEJ:1714

CHROMA BOARD

VTONANNA

SYNC SIP

750

L2,1 1212RED DOT TEL DOT 52

Call100/055

C ITOne.

5%Ao

*C227

Lros IIsec Tow .D 03T

511Ann

5%

112.

02.5400 11K5%

At it*5

Cl"L204 ft 1.0MLA 25F

VIDEO IT BOARD

1AS 0000

RDOST

S° TO DEFL 10 FM

010400011.

AUDIO OUTPUT 35

5000

.7011270

010V

3404MON

MAKTNESS

,25,/

VA

*--15%00 Fg2: .;o

TOJj400

7101A1.00

01.1TINTTRANS

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131TO .400

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37.16I Una

51.13300

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15131?

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1600

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11111111111111111111 JunctionCR702A & B

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30V P -P

JunctionC522 & R529

4111111111% 15V P -P

1

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TOME.

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RAWIT ANAL

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145V P -P

V501-9

tor

60V P -P

V706-2

111112

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5, -- ,.

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1,

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1.612200

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120

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TO 01.1HOW PULSE

C401000

ISA25.211

GREENSCA .C1103

1000

1.13MEGREDSC.

VIDEO CONTROL BOARD

NA

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900CHASSIS

400 CONTROL WEL300 DEFLECT..500 ODE 0

700 000.4000 00

COWROENCI

010625AP22A25GP22APICTURE

TUSE

TO HO

I WOCATES 1611010117011 WW2° 10.1.101. 2%

WOW INCPX44 LOOM sec or PC soPcmccown 010119 CAPAciTANCE VALIAS ------- T..

I ARE A 110/10.3011a CAPACITANCE VALUEI Of I /10 LESS

Mt A NICROFARADSALL VOLTAGES PCloSto wiTH NO510.1 EXCEPT 1.5 IDENTIFIEDWITH AND PITMAN (

SCHACE 0OLTASES on Nunn RIM 0411.19 ON AA .000.0 TIM AFC DEMAT SWITCH

LOCATED ON 11403

la - PRODUCTION 0.0

Peak to Peak voltages measured using a keyed Rainbow Color Generator.Some voltage values and waveforms will vary depending upon the controlsettings and the type of equipment used.

400V P I'

V501-8

ill:11,01;1;1111111111

111111111,111 t

I5V P -P

V710-7

I 1V P -P

V502-2

10111111101001111111111

,pv p.p

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V104-2

105V P -P

V7I2-2

1250V p p

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*.6111,Aw-AINW 150V P -P

V705-7

COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN OJIBWAY BUILDING. DULUTH. MINNESOTA 55802

1104RCA VICTORTV ChassisKCS165 Series

AUGUST 1967

ELECTRONIC 21-77=Lpidia 3IrTECHNICIAN


.11.11c 41111111111::

(91

TP-3

SECOND LITECTORVERTICAL RATE 2V P -P

OV201 PIN 1

SYNC PLATEHORIZONTAL RATE 55V P -P

V205 PIN 92

VIDEO OUTPUT PLATEVERTICAL RATE 100V P -P

O V205AGC

HORIZONTAL

PIN 2GRID

RATE 35V P -P

O V205 PIN 3AGC PLATE

HORIZONTAL RATE 400V P -P

V206 PIN 9VERTICAL OSCILLATOR GRID

VERTICAL RATE 160V P -P

wromielffillemm!-.

V206 PIN 2° VERTICAL OUTPUT GRIDVERTICAL RATE 25V P -P

V105 PIN 1° PICTURE TUBE GRIDVERTICAL RATE 110V P -P

12 SR201 ANODEHORIZONTAL PHASE DETECTOR


0 PW-200, TERMINAL "L"VERTICAL OUTPUT TRANSFORMER


11 SR201 CATHODE JUNCTIONHORIZONTAL PHASE DETECTOR


TP-40 HORIZONTAL SINE WAVEHORIZONTAL RATE I8V P -P

V101 PIN 915

PW-200 TERMINAL "T"0 HORIZONTAL OUTPUT GRID 145V B RIPPLE

HORIZONTAL RATE 100V P -P VERTICAL RATE 1.5V P -P

0 C246 8. C235 JUNCTIONZONE 2B, PW-200


SYMBOL DESCRIPTION

RI 12 - control vol with 5101RI 13 control brightnessR226A.B.0 control contrast vent 6 horiz holdR257 control vert sizeR260 - control vert lin5101 - switch port of R112

tuner KRK137Atuner UHF complete

811412 KIW

TT1OUV1g

101

TO AGC .1

C1031

.221

145V

8106TO j 330

VHFTUNER

C101 -d section elect 121 798

A - 250µ1 200vB -400uf 175vC - 500.0 175vD-5ut 150v

cCi1032 2 3280 ±20% LO1 ±-5 %

Uri c0er,ozc0NI 500 part of yoke 121236

0C109 - 2700 :t5% 3v ceromic Ni 500 . 121224

.

C257 - .0039µ1 ±10% 100v mica

CR201 - diode det 112524F101 -fuse 2 1/21n. 34AWG

CR101 - diode silicon rectifier 1N3 1 94 113998

RF101 -Luse resistor 211.9A 1210861102 - RF choke 8.21.th 1073851202 - RF choke 114315735

1203 - 560µh 1144881204 - 36ph 1160561205 2.7szh 1074631206 - 2700

11542714461207 - stabilizer 181210 RE choke

12148811869PW200 -circuit printed complete less tubesR103 - 4711 ±-5% 7w WW 121229R104 - 1611 ±5% 7w WW 121228R114-126 1w 512312R210

2 3.3K ±5% metal oxide121230R2I0 - 3911 ±5% metal oxide

22817810

R271 - 1.36 ±5% metol oxide

4

22709714

R216 - 3.36 -:=5% filmR220 - 3K ±5% metal oxideR223 - 5.66 3w 104

228710R275 396 ±5% metal oxide 227104SR201 - diode selenium 10

RCA 1102 - horiz output 1212139474

PART Na 7103 - vert output 1212121104 - audio output 121803

120395 T201A,B - 4.5MHz 114489121220 1202 - snd IF 118411121222 1203 -good 118410

...121223 1204 - 47.25 trop 113097121221 1205 - IF input 113097

T207 -- pm IF121254 T208 - pia IF output

109158114317

121088 yoke deflection 121211

7'

V2010

I

I

I

I

Ir

/260118APW200

R202 C201820 .01

820182K

7201A 02010213.2.

33I°

391

R2I233000

L210

"NS.

0217 C222

2t

:L202 t ;27204

C220

IFF211

1,001IK

16

8239i MEG

On.

T202

0202

I.0018R204 020711311

1.0022

0202A

1/2t7BFilSOUND OCT

0203

4J D61ST Pix IF

0218 0210856 T II 39

0221

V20I3A

1/2I ',CVO40.34AGC

7

8200 R206470 "007

ON/OFFFVOL.

R112

IBRIGHTNESS0113

JA1-1*-,$101

CJ

k0

T202

T203

0

R112 1MEGCurrOx 02026VOLUME

r-1203IC6123 '0°

I ,

R203 C208 R207560 .001 4707

0211

.047

C212.01

V21713F11

T207

OF 101

o 20'1

CPT -

0T255

T204

L207

0

V101

ERT OUTPUTTRANSFORMER7103

0 000

AAA

R226 P226 R226-A -8 -CCONTRAST VERTICAL HOW HOLD

KCS165 Chassis Layout Drawing

7104AUDIO OUTPUT

II .."vC2151.022 I

OS,

-4-408213150

R21706

+mar.-4-1450

C)4111TP3

02044JC6 r -7 L205

T207 290 PI X IF

*1400.

CR201 2.70

mov.I 7208

; 120,0 c

4riov. I

of -W7 L3E0 I L203 : 4.56AGZ. CO3

I

A__.-

1:226 1

5600 .TRAP To TM:.

0225680 L_

,--_ 1_-r _I R220437 v. 0 3000

vvsse1/211KV

VIDEO OUTPUT

R223 Ft2255600.3 820

0226A25K

CONTRAST

R219470

7

450.R2221800

C230.2V

16808221 -R229

114501154'

Pita

-1SI

NOTES: 0.1000ALL RESISTANCE VALUE3 ARE IN OHMS.

ALL RESISTORS ARE 1/2 WRIT. EXCEPT AS INDICATED.

ALL CAPACITANCE VALUES LESS THAN 1,0 ARE IN ;if,1.0 AND ABOVE ARE IN yy f, EXCEPT AS INDICATED.

DIRECTION OF ARROWS AT CONTROLS INDICATESCLOCKWISE ROTATION.

INDICATES 5% TOLERANCE

VOLTAGES MEASURED WITH "VOLTOHMYST. 0 WITH NOSIGNAL INPUT Es SHOULD HOLD WITHIN ! 20% WITH1200 AC SUPPLY.

R28AB

R280

C229 L2066600

2701,I1--0-,130,-4.----5'

1-C216

15

KSR227 822822K 270K

7

0250 TP4.001

I0

0 C24 -*-126131

34 C252 I0233 68 390K

6801I"Qa

4U70R269

02671

*Lae

1

150K- - -7.,

_,,

I-Lsrao, j

560K

02700233.... 68K

R276128

0034

R274 R27233K 1211

*ROY

02018

,...-7,1/26C418A :Z2R22127K

C2468248 .00476800

R2493.9MEG

R264 R246334 15K

02571 I

.0039-1,L 207

G

160

0264.3

/R266390c25641 C261 4700 I mEG

025111

R275 1330

0254 e R I

.05611300

13

7 -Iv.V207

8F07IIORIZ OSC

3

396 R226C60K00012 HOLD

C255.0033

vl

C237 10238.0039 272 7

-8247 Li.-150K

02068

1/215KY8VERT. OSC.

C240.033

02321300

828222 MEG

C231.015

R235471(

Ri 1190K313141GHT

01762

p 1

0

1.5

-1C5,,KtoiD

AF115°V

C2321.033R232

1K

V105

12 CNP4/310AVD4

I KINESCOPE

I

R255

V206A

P215KY8VERT. OUTPUT

413ov

L

3111-Or

{0251 I El 1-E"K8260

f- Pczog.68K-1220K 0 IimEG I T- 1.n117245 R254

VERT LIN R263100K-4, 0.0027

390

41 1Ci("Ca50111

R261330K

V1014

1/233GY 70ORIZ OUTPUT

t R10547

B

145V

00.3082563300

R262L8MEG 9268

1500

R2268 8257750K 35011VERT NOLD VERT SIZE

11(

R25912001560 7

2

I VERT7103 TEL

i OUTPUT

K, 1 BLU TRANS

_C244I

L

-.0613

+1450 -

AE

R102

12115 R110680

isnv. 330 350

Y y _WIDTH

V1010

L102 l/233GY7112° DAMPER

011-5 .4.411,4

8101330

8

C109 rT 11270

9 II-

art:"Lle2n.

KRK 137 1 0105

361(5 6CG8A12CNP4/1

IIKVBV205

3v3AV84TUNER

3I

4

v2078E07

S 4

020342D6

V2044206

V201601184

V202 0206178F11 15608

5 4 5 4 S 4 5 12 I 5

11412Hil 010 09 08 L201

I .cgo117 146 115 04 113 02 HI

I 01,c3,9 ., 0249

4MMIM.

V101

I 336Y7

4I

12

PW2011

0106680

,30.T

01018 CIOIA cm,4000'250011175V 2002 - =

01041647W

V102

1 X2 BNV RECT

Rill 2.2

8107IK

4450

rYOKE

010243

L107

L108 106

8106180K

110!02 VERT I

L COLA 031LS

0107.047 5101

ic,°5.1 5 -F34AWG

8102INTERLOCK

EFIRrrt---)

500VFILTERED

6051200

POWERSUPPLY

1104 COPYRIGHT 1967 BY ELECTRONIC TECHNICIAN OJIBWAY BUILDING, DULUTH, MINNESOTA 55802

PrecisionApparatusintroduces 5 new models; now acomplete line of quality testequipment for service techniciansFor over 30 years, professionals in industry, service, laboratoryand educational fields have relied on Precision Apparatus TestEquipment. Today, through the experience and marketingknow-how of Dynascan Corporation, Precisicn Apparatusoffers even greater reliability and performance-maximumversatility-in all applications. By every standard, they are thehallmark of quality in test equipment.

NEW! A MUST FOR COLOR TV ALIGNMENTMODEL E-410C-SWEEP GENERATOR AND MARKER ADDER

Wide range, frequency modulatedsignal source combined with MarkerAdder circuitry designed for thealignment of color TV, FM and otherhigh frequency wide -band receiversand circuits. Solves marker visibil-ity and overloading problems. Fur-nished with a 4.5 me crystal and 5output cables. $169.95

NEW! MODEL B-12-REGULATED POWER SUPPLYA reliable source of variable, regu-lated DC plate voltages, and biasplus AC filament voltages ... withexclusive 6.3 VAC and 12.6 VACsupply. Perfectfor service bench andcircuit development, it offers regu-lated DC voltages from 0 to 400 volts,and a bias supply from 0 to -150

volts. Each output is variable throughout its range. Rugged, double -jewelled, D'Arsonval meters mounted on the front panel. $99.95

NEW! MODEL B-10-BATTERY ELIMINATOR & CHARGERTwice the filtering provides .15%ripple! Designed to meet rigid, low -ripple output requirements of mod-ern transistorized automobile radiosand other electronic equipment of 6and 12 volt ratings. Does not requireadditional investment for externalfilter adapters. Functions as an effi-

cient, reliable battery charger with special high -current output .atseparately labeled terminals. $59.95

liphallmark of quality in test equipment Where Electronic Innovation Is A Way Of Life

Tube supplement information now available for all Precision and Paco Tube Testers.. . . for more details circle

NEW!MODEL V-95 PRO-FESSIONAL VTVMMore accurate read-ings on huge 7' mir-rored scale. Special0.5 VDC scale forprecise transistor

circuit analysis. Zener controlled internalpower supply obsoletes ohmmeter batter-ies. Two-way protection: transit switchposition and anti -burnout shunts preventmeter damage on the job or on the road.Single test probe eliminates cable tanglesand lead shuffling. Rugged walnut -grainmetal case; name -personalized handlestops "borrowing." $79.95MODEL V-75 with 41/2" meter. $59.95

ES -550B WIDE -BAND OSCILLOSCOPEDeluxe scope; extra brightness; extra highsensitivity. Unique calibration voltagemakes measurement easy. $279.95

E -200C MULTI -BAND SIGNALGENERATORUnique AVC substitution system for totalaccuracy. 88 KHz to 400 MHz, hand -cali-brated. $119.95

. * 0 0 large CRT screen give

more than 6" undistorted deflection. Auto-matic horizontal synchronization includes60 Hz sinusoidal sweep for TV and FMalignment. Special 500 KHz sweep makesit easy to see complete 3.58 N1Kz burstsignals; ideal for color TV. Exceptionallylow distortion. $169.95

120M VOMPh% DC accuracy. Exclusive extra -lowR x 1/10 scale reads to 0.1 ohm.Transit andburnout protection. Mirrored scale. $65.00ALSO: MODEL 120 with DC. $56.00

E-310 SINE & SQUARE WAVEGENERATOROnly moderate -cost, low-cistortion, 5 Hzto 600 KHz wide band gererator. $199.95

NEW!MODEL S-65PUSH-PULLOSCILLOSCOPEWide band amplifica-tion, DC coupled, zeroto 5 MC. High verti-cal sensitivity and

The Complete Line That Sets Industry Standards

PRECISION APPARATUSCivision of Dynascan Corporation1801 W. Belle Plaine Aver LieChicago, Illinois 60613

122 on postcard

19AUGUST 196 7

The hottestthing inelectronicshardly getshot at all

(RCA's solid integrated circuit, that is)

With the tiny chip there are few heat problemsand low power consumption. And because inte-grated circuits run cooler, parts can be placedcloser together to enhance design convenience.One day you may see stereo cabinets with morereal storage space, and color TV sets the size ofa transistor radio. At RCA Victor we've taken a

step into tomorrow by using integrated circuitsnow in new color and black and white TV and instereo phonographs. They're not only the mostadvanced productsof their kind, they The Most Trusted Name

are more reliablethan ever before.tel

in ElectronicsTrnk(s).:

20 ELECTRONIC TECHNICIAN

PublisherRON KIPP

Managing EditorJACK HOBBS

Technical EditorJOSEPH ZAUHAR

Associate EditorPHILLIP DAHLEN

Field EditorRICHARD CLAYTON

Production EditBARBARA BURNIAN

Art EditorKEN McSHANE

Circulation ManagerRUTH GELINEAU

Manager, Reader ServicesJCHN KESSLER

Advertising ProductionMAGGIE KANE

GENERAL OFFICESOJIBWAY PRESS, INC.

0:ibway BuildingDulath, Minn. 55802Phone: (218) 727-8511

Telex: 029-4417

PresidentMARSHALL REINIG

TreasurerGREG BLODGETT

Executive Vice PresidentDEAN MYHRAN

Vice President, MarketingJOE WOLKING

Vice President, EditorialBEN MARSH

Vice President, ProductionHARRY RAMALEY

Circulation DirectorLARS FLADMARK

Art DirectorJAMES GHERNA

Ad Production SupervisorWARREN BODIN

NEW YORK OFFICES71 Vanderbilt Ave.

New York. N.Y. 10017Phone: (212) 686-2200

President. Publications DivisionROBERT EDGELL

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Manager, New York OfficeDON GENOAR

CHICAGO OFFICES43 East Ohio Street

Chicago. Illinois 60611Phone: (312) 467-06-M

Telex: 02-53549

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MARKETING REPRESENTATIVES

New York: (212) 686-2200RON KIPP

Chicago: (312) 467-000ED KELLY

ELECTRONICTECHNICIAN

WORLDS LARGEST ELECTRONIC TRADE CIRCULATION

AUGUST 1967 VOL 86, NO 2

39 THE STATE OF SOLID-STATEAn ET TEKLAB report covers developments in solid-state equipmentand test instruments. It brings you up to date in this area, includinglatest information on integrated circu try

43 UNDERSTANDING MODERN AGC CIRCUITSThe 'ifth article of this in-depth series digs into the com-ron-senseprinciples of troubleshooting today's AGC circuits

46

49

SOLID-STATE TV SERVICING THE EASY WAYThe "old pro" tells you how to do the job easily and save time

USING AUDIO TEST AND ALIGNMENT INSTRUMENTSPart three of another in-depth article series continues with the "how-to' approach in using test instruments for audio equipment main-tena.-ice and troubleshooting

54 SEMCONDUCTORS FROM A TO ZThe thirteenth article in this important in-depth series covers theRCA IC201 circuits and how they function

59 TI -E APPRENTICE AND THE PROThe second article of this series-in the midst of a critical t-echnicianshortage-continues with the day-to-day experiences of an apprenticeand the "pros" with whom he worked

22 LETTERS TO THE EDITOR 74 NEWS OF THE INDUSTRY

28 EDITOR'S MEMO 78 CATALOGS & BULLETINS

32 TECHNICAL DIGEST 80 ADVERTISERS' INDEX

66 COLORFAX 81 READER SERVICE CARD

68 NEW PRODUCTS

COVER

The more than 80,000 service -dealers and technicians who read ELECTRONIC TECHNICIANare participating heavily in the upsurging sales of transistorized portable AiVi/FM radios.

TEKFAX 16 PAGES OF THE LATEST SCHEMATICS

AIRLINE: Color TV Model GHJ-8247A,57ACANADIAN GENERAL ELECTRIC: TV Chassis M649CORONADO: TV Model TV 21-9367AMAGNAVOX: Color TV Chassis T920 SeriesPHILCO: TV Chassis 17C21,A,V,AVRCA VICTOR: TV Chassis KCS165 Series

CJIBWAY PRESS, INC. Zit .0.

Group 180

ELECTRONIC TECHNICIAN is published monthly by Oilbway Press, Inc. Subscription Rates:One year $5.00, Two years $8.00, three years $13.00 in United States and Canada. OtherCountries: One Year $9.00, two years $14.00, three years $18.00. Sing.e Copies, 601.Second Class postage paid et Waseca, Minnesota arid at additional mailing offices. Copyright1967 by Ojibway Press, Inc.POSTMASTER: Send form 3579 to ELECTRONIC TECHNICIAN, Ojibway Bu:Iding, Duluth,Minnesota 55802.

AUGUST 196' 21

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ji LETTERSit TO THE EDITOR

'Aerosound' 20/20 StereoCan anyone advise me where I

can locate a schematic for an "Aero-sound" 20/20 Stereo Hi Fi amplifier?

JAMES CARTER10417 Montrose Ave.Bethesda, Md. 20014

Nct knowing the manufacturer'sname, we were unable to locate aschematic.-Ed.

Needs HelpI am unable to obtain information

on using my Precision model 650tube tester for checking CRTs. Thechart I have is dated August 1962.Can any reader help me with a moremodern chart? Answer via ET.

DONALD W. LAUGHLINBelle Chasse, La.

. I need schematics and instructionmanuals for 1) CES Electronic Prod-ucts micro miker, model 402D, and2) same for a Hazeltine Model OAP1frequency meter oscillator. Answervia ET.

DAVID M. AMIDONSierra Madre, Calif.

Has Trades Institute SchematicI can furnish a schematic and align-

ment date for a Commercial TradesInstitute model TV321. Contact medirect.

WILLIS WALTERS295 Glenn Ave.Carey, Ohio 43316

Finds 'A to Z' Article ValuableYou are indeed putting out a great

magazine and doing a great servicefor service -dealers and technicians.May you long continue this service.I have come to realize the value ofthe series "Semiconductors from A toZ" and I am saving the articles. Thenew series, "The Apprentice and thePro," also looks very promising.

VINSON BLUERichmond, Calif.

FYIThe 19BR5 tube will replace the

UM80. If the tubes are not availablein certain areas I can furnish a 19BR5upon receipt of certified check for $4.

PETER KNIP71 Tunis BayWinnipeg 19, Man. Canada

... for more details circle 114 on postcard22 ELECTRONIC TECHNICIAN

/1.111I11.11M4AN11111111111111111.

/11M1111111111.1%

122L1113

For window -size blow-ups ofthis message, send 100 toSprague Products Co., 65Marshall St., North Adams,Mass., to cover handling andmailing costs.

ARE TV SERVICE DEALERS GYPS?Every so often, some magazine or newspaper soundsoff about TV -radio service shops.

"Service technicians are a bunch of gyps," is thegeneral theme. "They'll clip you if you don't watchout."

They might just as well write the same thing aboutdoctors, lawyers, storekeepers, auto mechanics-oranyone else. There are gyps in every line of business.Actually the percentage in TV -radio is lower thanin most.

The average service technician is a hard-working,straight-shooting individual. Rather than gyp customers,he is far more likely to spend more time on a job thanhe knows he will be paid for-simply as a matter ofpersonal pride in doing things right.

We recently heard about someone's TV set goingbad. A service technician called for it with his truckand returned it in good working condition within 48hours. His bill came to $10 for service plus $2.68 forreplacement parts.

The set owner argued that this was too much-yet hewould never dream of complaining to the medical spe-cialist who charged him $10 for a 15 -minute officevisit; the lawyer whose bill for writing a simple will was$75; or the garage man who laughingly admits that hecharges $5 for "just raising the hood" of a car.

In one of our very large cities, the Better BusinessBureau received fewer than 500 complaints about serv-

ice in a year. Most of the complaints came from folkswho expected first-class reception in doubtful fringeareas; who tried to operate their sets without suitableantennas; or who had bought sets "wholesale" at ridicu-lously low prices from cut-rate dealers who could offerlittle or no service.

Actually, it takes almost as long to become a goodservice technician as it does to train for any otherprofession. Beyond this, it calls for regular study tokeep up with the constant stream of new developments.Also, it requires a surprisingly big investment in testinstruments, manuals, and other shop equipment. Themodern TV or radio receiver is by far the most intricatepiece of equipment the average person ever owns oruses.

Service technicians are not fly-by-night businessmen -99 out of 100 run their businesses properly. The otherone per cent-the gyps-can usually be spotted a mileaway. Nine times out of ten, they are the shops thatfeature "bargain" prices and ridiculously liberal servicecontracts. And their victims are generally set owners whoexpect to beat the game by "getting somei'hing fornothing."

Good television sets or good TV service are notthings to be bought on a "bargain counter" basis. Setowners who recognize this aren't likely to get gyped.

Instead, they'll find that they get more real valuefor their television entertainment dollars than for anyother dollars they spend!

THIS MESSAGE WAS PREPARED BY SPRAGUE PRODUCTS COMPANY.DISTRIBUTORS' SUPPLY SUBSIDIARY OF SPRAGUE ELECTRIC COMPANY, NORTH ADAMS, MASSACHUSETTS, FOR . . .

YOUR INDEPENDENT TV -RADIO SERVICE DEALER... for moro details circle 128 on postcard

AUGUST 1967 23

Listen!

Help stamp

out backseat drivers!

Millions of Americans arereplacing the hack seatdriver with a back seatspeaker. It's all part of thebooming Rear Seat/RearDeck loudspeaker marketwithin the automotive field.Ten million cars worth!

Jensen's Rear Seat/RearDeck speaker kits help youget your share . . . andmore! The attractive "see-thru" packaging of theseShow Pack models, instantsolderless connectors andan assortment of Jensenbonus features (whizzercones, heavy duty magnets,solid domes, dust drainholes, etc.) all team up tomake your cash registerring. (Also available indi-vidually boxed.)

Insist on Jensen RearSeat/Rear Deck speakerkits.

JensenJensen Manufacturing Division. The Muter Company,6601 South Laramie Avenue, Chicago, Illinois 60638

. . . for more details circle 116 on postcard

TO THE EDITOR

Needs Weston Tube Tester BookletCan any ET reader help me locate

an instruction booklet for a Westonmodel 798 tube tester?

COL. LEONINO JUNIORRua Raimundo Correa 19-Ap. 502Copacabana-Rio de Janeiro, Brazil

The Pro and Con of ItI have been a subscriber and avid

reader of ET for many years. I findthat of all the trade publications Iread, as far as a technician's view-point is concerned. that you havethe most comprehensive magazine inthe industry. Therefore, I was a littlesurprised to read your "FormulaKick" editorial in the April issue. Thispro and con licensing argument isof course getting quite old and badlymaligned but the facts involved in thecase, and the need, do not change.All those who oppose licensing con-tinually and repeatedly fall back onthe argument of self-governing, self -certifying, self -policing and self-clean-ing as the great cure. Unfortunately,the people at whom licensing is di-rected never joined an association andnever self -license, self -govern, self -certify, self -police of self -clean them-selves and you will find that the BBBin almost all communities, even thoughthey have publicly opposed licensingmany times, admit themselves thatthe same people do the same cheatingyear after year.

Unfortunately, self-control and con-science do not motivate these individ-uals whatsoever. On the other hand,if they stood to lose a license tooperate this dishonest business, itwould motivate them into either goingout of business or becoming honest.

Again, I don't disagree with youreditorial except for the fact that inopposing licensing, the only solutionyou or anyone else who opposes ithas to offer is self -policing. Duringthe 20 years I have spent in thisindustry, self -policing has not workedand I see no reason in the next 20years why it would be any different.Furthermore. I don't think that any-one in the industry, no matter howviolently he is opposed to licensing.could produce any evidence that wouldalter these facts.

Again, those who support licens-ing intelligently do not offer it asa panacea, nor do we even hint thatit is, but it is far better than nothingand has proven to be so in all areaswhere it has been put into force.

I think the record of its actionsspeaks for itself.

GREGORY BARKOUKISNEA/OJT Coordinator

National Electronics Assoc.859 Coburn St.Akron, Ohio 44311

. . . Your April Editor's Meino,"Formula Kick," was sent to me byone of my associates: I could notagree with you more!

It is indeed heartening to find atleast one writing man in our servicepublishing field who is ready, willingand able to speak out forthrightlyabout this licensing regulation phobia.

I and my associates have for yearsfought licensing in Illinois, and it hasalways been our belief that it is wrong,unworkable, and where it has beenput in-against the apathy of thosemost affected and by legislators withone eye on the ballot box-that overthe long pull it became nothing but an-other nail in the coffin designed forthe "free enterprise" system, underwhich this country grew straight andstrong.

And also where its proponentswould have you believe that it didwork miracles of self -enforcing honestyand morality, over the long pull,all that it did accomplish was to sweepthe "hot shots" under the rug, whocould and will work the licensinggambit for all it is worth, as a meritbadge to really steal legitimately.

If all the fellows who have workedso enthusiastically to push for thisthrough the years had put theirenergies into the channels of raisingthe sights of their fellow technicians,and spent their money in this activity,we all would have been much furtheralong in the public esteem.

HOWARD WOLFSON, SecretaryARTS of Illinois

25 E. Congress ParkwayChicago, Ill.

The fact is, although it has inde-pendently commented on the subjectfrom time to time, ET has never takena hard-nosed position for or againstlicensing per se-and does not intendto-since it is devoted entirely toupgrading the technical and businessknow-how of service -dealers and tech-nicians.-Ed.

Needs AMC SchematicI think your "Letters to the Editor"

columns are a wonderful source of in-formation. I need a schematic for anAMC radio, model 7TAF. Apparentlythe manufacturer is out of businessand I can't get one. Can any readerhelp me? Answer via ET.

ANDRES A. VINENTFayetteville, N.C.


New low cost.

New ease of operation.

No waiting. No warm-up.No adjustments.

Brightest patterns in the industry.

MODE.. 1242 SOLID STATE COLOR GENERATOR

OFF CC 1C1

GUN I* Lt ER

I IPA -TERN

The *g1242 Color Generator is all buOne$$There's nothing else like it. The all -newB&K 1242 represents the highest state ofthe art today. Go ahead ard compare it;it's unique.

U:trastaole solic-state circuits makeartiqJated -eating eleme n1s unnecessary.The 1242 works ins:antly in all service

enviiconments- no waiting. no warm-up,no adiust-rients. Other units have up to3 times as many frort panel cortrols. Forease of operation, the 1242 has just two:colo- level and selector switch. Itprov des Jots, crosshatch, horizontal orverti.zal :Ines, and cclor bars. And theseare tie at arpest, brightest patterns inthe industry.

The 1242 handles easily, too. It's thesmallest lightest -weight color generator!Rugged, le o; it's all steel, with storage

BM( Division of Dynascan Corporation1801 0'. EeHe Plaine Chicago, III no's 60613

Where Electronic Innovation Is A Way Of Life

. . . for more details :ircle 106 cn postcard

space for leads. It's transformer poweredand complete with leads. Calls take lesstime and you make more money, becauseyou can go from a cold or hot tuck intoa home and get right to work.

On every count, the pew B&K /242 isamazing. In time sa%ed, it will pay foritself in just a few weeks -especially atthis low price: $99.95

"the ANTENNA that captures the RAINBOW"No two reception areas are alike in the number of stations, UHF and VHF,station channel frequencies, and signal strengths.FINCO has developed the Color Spectrum Series of antennas -"Signal Customized" -to exactly fit the requirements of any given area. There is a mode scientifically designedand engineered for every area, even the most troublesome, and for all combinationsof signal conditions.Engineering studies show that a receiving antenna should have mcre gain as channelfrequency is increased -that is, channel 6 more than channel 2, zhannel 13 more thanchannel 7, and UHF from channel 14 on up...

1-to compensate for signal strength loss2-to compensate for down -lead loss3 - to meet receiver requirements for more signal to operate properly

FINCO Color Spectrum Antennas obtain this frequency depended characteristic through anewly developed principle of spacing between elements. Gain increases as frequencyincreases. This new FINCO engineering break -through, combinec with superior flatresponse patterns and unusually high front -to -back ratios, assure the finest COLOR andB & W reception possible... everywhere.

Write for full information on "Signal Customized" Antennas:

THE FINNEY COMPANY34 West Interstate Street Dept. 1 10 Bedford, Ohio 44146


flE7117III Ill

iyirild easteifilarfor leer /earn

Check this chart -:or the FINCO "SIGNAL CUSTOMIZED" Antenna best suited or your area

STRENGTH OFUHF SIGNAL

AT RECEIVING/ ANTENNA/ LOCATION

*

Strength of VHF Signal at Receiving Antenna Location

NO VHF

*VHF SIGNAL

STRONG

*

CS -V3

$10.95

VHF SIGNALMODERATE

*

\ U\

CS -V5 CS -V7

$17.50 $21.95

VHF SI3NALWEAK

*

....:

CS -V 0$35.95

VHF SIGNALVERY WEAK

*

NO UHF -CS -V15 CS -V18

$48.50 $56.50)

S

UHF SIGNALSTRONG

CS -111

$9.95

\ \

CS -Al

$18.95CS -B1

$29.95CS -C1

$43.95

4,-

CS -C1

$43.95

UHF SIGNALWEAK

i

CS -U2$14.95

?e

11--

CS

$22.95

-______

-A2 CS

$49.95-B3

-r -

CS -C3

$59.E5CS -D3

$69.95

>

UHF SIGNALVERY WEAK

CS -U3$21.95

...""-

CS -A3

$30.95

\:Igitle**#

CS

$49.95-B3

\4171414°11*"..*.

CS -C3

$59.95

\&0"illtw

CS -D3

$69.95

)>>

AUGUST 1967

NOTE: In addition to the regular 300 ohm models (above), each model is available in a 75 ohm coaxial cable downleadwhere this type of insta lation is preferable. These models, designated ' XCS", each cone complete with a compactbehind -the -set 75 ohm to 300 ohm balun-splitter to match the antenna system to the proper set terminals.

... for more details circle 113 on postcard27

ALIGNMENT OSCILLATORSDESIGNED TO MAKE SERVICING EASIER

BOTH NEW FROM INTERNATIONAL

MODEL 812(70 KHz - 20 MHz)

The Model 812 is a crystal controlledoscillator for generating standard

signals in the alignment of IF andRF circuits. The portable design is

ideal for servicing two-way radios, TVcolor sets, etc. This model can bezeroed and certified for frequencycomparison on special order. Individ-ual trimmers are provided for eachcrystal. Tolerance .001%. Output

attenuators provided. Battery oper-ated. Bench mount available.

Complete (less crystals) $125.00

Write for catalog

MODEL 814(70 KHz - 20 MHz)

The Model 814 is identical in size tothe 812. It does not have individualtrimmers for crystals. Tolerance is

.01%. Battery operated. Bench mountavailable.

Complete (less crystals) $95.00

Both the Model 812 and Model814 have positions for 12 crys-tals and the entire frequencyrange is covered in four steps.

INTERNATIONAL.w- wfw

CRYSTAL MFG. CO., INC.10 NO. LEE OKLA. CITY, OKLA. 73102

. . . for more details circle 115 on postcard28 ELECTRONIC TECHNICIAN

J EDITOR'SIt MEMO

They Must StandardizeTechnological changes take place in

the electronics industry at a fantasticrate. These changes require new serv-ice techniques and may produce un-necessary headaches.

One recent change has come withMotorola's introduction of a transis-torized color -TV set. If a componentgoes bad in the set's audio circuitboard, for example, the technicianmerely unplugs the board and returnsit to his supplier who will replace itfor about $6, if the warranty hasexpired. Other plug-in circuits-form-ing the major portion of the receiver-are replaced in a similar manner at aslightly greater cost. The cost of re-placing these boards may frequentlybe less than the value of the techni-cian's time if he replaced the defectivecomponents on the board.

Some technicians have speculatedthat the development of modular com-ponents would endanger their futurelivelihood, since a few TV set ownersmight attempt to service their receiversby replacing modules. This is highlyunlikely since the owner would notknow which module is defective. Atechnician's skill is needed to deter-mine which module is causing thetrouble -symptom.

The real danger, however, mayresult from the industry's failure tostandardize future modular microcir-cuits. It is already becoming increas-ingly difficult to catalog the wide as-sortment of integrated circuits cur-rently being developed. Microcircuitsand simple integrated circuits will bemass produced for modular use in fu-ture receivers. The nature of these"beasts" prohibits their repair, andonce they have developed a flaw, theymust be replaced. But will techniciansbe able to maintain an adequate in-ventory if new modular circuits aredesigned for every new receiver modelintroduced?

In the case of Motorola's new set,as an example of things to come, aspokesman acknowledges that the av-erage service -dealer will probably notbe able to maintain a supply of theircolor -TV set's plug-in circuit boards.

Unless the electronics industry be-gins an immediate program of stand-ardization, servicing procedures maybecome a time-consuming necessity.The number of house calls may double.TV sets may sit for days unrepaired.And technicians may find themselvesworking more hours as "delivery boys"than as technicians.

Getting a hernia and not getting paid for it?

Switch to Elmenco dipped Mylar& paper capacitorsand you won't have to worry about call-backs,lost profits, broken reputations or brokenanything else.The only ordinary thing about them is their price.You get capacitors that meet the requirements ofhigh -reliability computer and missile systems. Youget capacitors that hold their rating at 125°Ccontinuous operation. Yet you get them at TVset prices.Elmenco dipped Mylar-paper capacitors come injust about any value you need from .001 mfd to1.0 mfd. And just about any TV rated voltage youneed, too, from 100V through 1600V.Ask your Authorized Arco Distributor to put themon your next order. Without fail.Tell him you're counting on his support.(While you're at it, ask about other Elmenco types:padders and trimmers; high voltage dipped micas.)

Arco ElectronicsA Division of Loral Corporation ICommunity Drive, Great Neck, N.Y./Arlington, Texas / Elk Grove Village,Illinois/ Pasadena, Menlo Park, California.1-3) CU PONT TRACEMARK.


Channel Mastersmashes the82 Channel sizebarrier!

Deep Fringe

Model 3661-6Same VHF gain as

Color Crossfire

Model 3610-G

Revolutionary VUtronic design*

electronically interleaves U and Velements for compact size without

Fringe area Model3661G has all UHF ele-ments contained withinthe over-all length ofthe VHF section

sacrifice of VHF gain.

A VHF only antenna withexactly the same VHFgain as the 82 -channelModel 3661G is alsopractically the samesize.

Usual design 82 -channelantenna would have tobe 34% longer to pro-vide the same UHF andVHF gain as Model3661G Color Crossfire 82

1967, Channel Master Corp., 'Patent Applied For

New Color Crossfire 02UHF/VHF Antennas plus FM/FM StereoTotally new concepts in UHF/VHF design are joined with Channel Master's provenCrossfire principle to produce the first 82 -channel antennas that meet UHF receptionneeds yet also provide unsurpassed VHF gain ... and with no appreciable increase inover-all size.

Here is another example of a major development from Channel Master Laboratorieswhere, as always, leadership begins with research.

Until now, antenna manufacturers have createdcombination UHF/VHF antennas by coupling a UHFsection to the front of a VHF antenna. To avoidcostly, unwieldy, and unsightly construction, thishas always meant sacrificing VHF gain. Now Chan-nel Master fills the 82 -channel gain gap with ColorCrossfire 82 antennas designed for metropolitan tofringe areas where maximum VHF gain is as im-portant as UHF reception power.

In addition to the famous Channel Master Cross-fire VHF Proportional Energy Absorption Principle,these new antennas employ unique series -fedfolded UHF dipoles with carefully engineered di-mensions so that they literally "disappear" andoperate as a perfect 300 ohm line at VHF frequen-cies...no "Iossy" couplers required as is the casewith the usual parallel -fed UHF elements.

And, of course, every Color Crossfire 82 antennafeatures Channel Master's famous E.P.C. goldencoating and rugged preassembled construction.

VHFDirector

HERE'S THE SECRETUHF

DirectorLow end UHF

1/2

UHFCirector

High end UHF

1/2

UHF Phase CenterController Insulator

2 UHF Wave -Lengthsoverall

VHFDirector

VUtronic design employs uniquedual -function co -linear directors (onall but three metropolitan models)serving both UHF and VHF sections.This permits space -saving inclusionof the 15 --IF elements into the physi-cal structure of the full -power VHFarray. The exclusive UHF phasecontroller "whiskers" boost UHFgain by making each full -wave di-rector the equivalent of two fullwave lengths.

Now the first and only complete line of full VHF Power 82 -channel antennas.

Suburban

36656

Near Fringe

Near Suburban

model3666G

Far Suburban

Outer Metropolitan Inner Metropolitan

More ChannelMaster CrossfireSeries Antennashave been soldand are beingsold...than anyother antenna inthe history oftelevision.

CHANNELMASTER

Ellenville, N.Y.

AUGUST 1967


31

11...47x ja!g rrg!':CZ"; ;;""",13 JIM 1117,..10 414.1.1 et

47,eI_ "

I (5111°:IrrriAniliMAA1 "9*.151AC

Making TV and FM Absorption TrapsTelevision and FM receivers are specially designed

to reject unwanted signals. Occasionally, however, in areaswhere undesirable signals are extremely strong, a problemmay appear. For example, adjacent channel interferencemay occur in areas where a customer wishes to watch adistant station and there is a local station on an adjacentchannel. Although correct antenna orientation and selectivetuning will usually help, the unwanted signal may stillcause interference. In such cases, a tuned trap will usuallysolve the problem.

RF interference is another problem that sometimespresents itself. This type interference usually occurs inareas where the set is located "next door" to a TV or FMtransmitter. These particular circumstances can causeinterference on several or all TV channels. On an FM re-ceiver, spurious signals may be received at several spots onthe dial, or in extreme cases, block out several or all FMstations.

In solving problems of an interference nature, it isoften desirable to attenuate (or reject) a specific frequencyor band of frequencies. In most cases, this can be doneby simply installing an absorption trap on the antennalead-in. Such traps may be quickly constructed by usinga section of 300-flat ribbon transmission line, terminatedon one end by a small trimmer capacitor. The other endof the trap is short-circuited for trapping VHF signals;

CERAMIC TRIMMER1.5- 28 pf TYPE A (VHF)

SHORTED

TYPE B (UHF)OPEN

whereas for UHF, the other end is open -circuited as shownin the illustrations.

Lengths of 300n line for typical traps follow: (Tuningtrimmer capacitance range in all cases is 1.5 to 28pf.)

ChannelsCh. 2-6 and FMCh. 7-13Ch. 14-50Ch. 51-83

Length "L"8in. VHF Type A3in. VHF Type A5in. UHF Type B3in. UHF Type B

These traps are installed by taping them to the 300nantenna lead-in. The effectiveness of the trap is controlledby several factors:

1. Position of the trap along the lead-in: The trap setsup a standing wave at the trapped frequency in thelead-in wire to the receiver. The trap should be movedalong the lead-in until the optimum trap placement isfound, remembering to retune the variable trimmer.2. Physical length of the trap: The length (dimension"L") may be varied and the trimmer adjusted accord-ingly. A longer trap tends to be "broad band."3. Coupling of the trap to the line: For effective oper-

V12

2413L5133

DMVER im

ation it is necessary that the trap be installed againstflat 300n lead-in. After final adjustment the trap canbe held in place by paper or vinyl tape. A convenientinitial adjustment technique is to hold the trap on the

ADJUSTABLECERAMIC CAPACITOR

VINYL TAPE 47-i?

5r*L 300 IL LINE

TRAP300n line with spring -loaded plastic clothespins. Theclothespins serve as convenient handles during the initialtrimmer adjustment and allow positioning along thelead in for optimum attenuation.

Practical use of the traps may fall into three categories:1. A trap for narrow band interfering signals.2. Trapping a broad band signal like a TV channel.3. A method for identifying the frequency of an inter-fering signal in the field.To reject a narrow band signal, the trap is coupled to

the transmission line and adjusted to the interferingsignal. The trap lengths given in the table will cover therange of frequencies from 50 to 890MHz. Remember toposition the trap along the lead-in for optimum rejection.

Trap circuits can attenuate a broad band signal (astrong TV channel) that is interfering with a weakerchannel. Because the trap will have a pronounced effecton the channel to which it is tuned it is very importantto check the performance of the receiver on the "trapped"channel, with and without the trap in place. In particular,a color TV should be checked with a color program. Ifundue effect is noticed, it may be necessary to "broadband" the trap circuit. This may be done in one of twoways: by increasing the length "L" of the trap and readjust-ing the trimmer or alternatively, by loading the trap witha resistor, typically 10K. Courtesy RCA Victor

ADMIRALRadio Phono Chassis 5V6, -6A and 5W6-Output Transistor Rapiaornant

A stud -mounted type output transistor, 57C6-14, wasused in early production, and is no longer available. Areplacement kit consists of a 57C6-10 transistor, an insulat-ing wafer and two plastic screws stocked under the originalpart number 57C6-14. The aluminum heat sink in whichthe original transistor was mounted also contains holesfor the 57C6-10, but they are not tapped. This can bedone easily with a 6-32 thread -cutting screw (1A51-4-24).The transistor must be mounted only with the furnishedplastic screws. Do not use metal screws for this purpose.


CANADIAN GENERAL ELECTRICColor TV Model M663-Audio Trouble

There have been reports of audio problems that canbe caused by bad lead dress in the audio circuit.

The leads of C313 and C306 have been found to bein contact with the envelope of the 12BF11 audio outputtube. The transfer of heat will cause distortion.

The solution, of course, is to bend the capacitors awayfrom the envelope so they are no longer in contact.

Color TV-New Picture Tube TypeAt present there are two types of 25in. color tubes

used in Canadian G -E sets. The only differences areas follows:

CharacteristicsHeater currentG1 cutoff at 440v G2Over-all length

25AP22A 25SP220.8a 1.3a-95 to -190 -75 to -16720.924 =0.375 21.123 =0.375

It can be seen that both tubes are interchangeable.There is one small modification - R124, the 0.0852.

RIO,1K

40

TO"J'

R'59R 10J TO "E. ISOK755100+400V

4400V

T IDI

WWEILA,20v TAPTAPE TO REDBLK LEAD

RED:BLK

5/02

ON.VOL

BYPASS WHENUSING 25SP22

3W resistor should be bypassed by a piece of buss wirewhen you use the 25SP22, the buss wire is removedif you replace a 25SP22 with a 25AP22A. The resistor islocated under the chassis near the power transformer.

GENERAL ELECTRICColor TV Chassis KC-Changing HV Regulator Tube Type

Regardless of the type of service being dcne on theKC chassis color TV, the high voltage regulator tube V17,with white printed code (white branding) is to be changedto a new type, as shown. Tubes having a yellow code andbranding are not to be changed. Chassis stamped EN378or higher do not require this change.

This tube type change should be performed regardlessof whether the TV is in or out of warranty. The old tuberemoved from the chassis is to be tagged with customer'sname and address, along with the model and serial numberof the TV set. Return the tagged tube to the nearest G -ETV distributor for credit or exchange.For 6EA4 use 6EH6For 6EF4 use 6EJ4For 6LC6 use 6LH6

After installing the tube, attach one of the new tubetype labels (packed with the tube) to the rear wall of theHV compartment and the other label to the outside ofthe cabinet back near the top. The information on thelabel will then indicate to anyone subsequently servicingreceiver that the new type tube has been installed.

ISwingin'

Combo

for

Top

Performance!

NJ C"=,g.E.r:

SEMI -AUTOMATIC

NEW SENCORE SM112B

SERVICE MASTER VP/M1VOMHere it is - the third generation of Sencore'sfamous Service Master - the two -in -one profes-sional instrument that saves your time, speedsyour service work, puts extra profits in yourpocket.

Just one function switch, one range switchand one probe provide all functions ofVTVM and VOM.

Voltage, current and resistance in 33 ranges- for acct.rate measurements anywhere,anytime.

VTVM operates from 115v AC for precisebench or lab work; battery powered VOMgives you a 5000 ohms per volt meter.

Lighted arrows automatically indicate VTVMscales.

Large, easy -to -read 6 -inch two percentmeter covers all measurements.

Handsome new styling in tough, vinyl -cladstee' case.

Optional high voltage probe attaches formeasuring up to 30,000 volts DC.

So why use two when one will do - the newSencore SM1123. Truly professional $19.95quality, and still onlyHigh Voltage Probe HP118 $7.95

1\J CD 1=1NO I MANUFACTURER OF ELECTRONIC AIAJNI.ENANCE EQUIPMENT

426 SOUTH WESTGATE DRIVE. ADDISON. ILLINOIS 60101


AUGUST 1967 33

3 -Way Combination

FREE SPACE STANDING WAVE

MAGNETIC ANTENNA

zEROSyOU

INR SIGNAL.

Discriminates BetweenDesired Signal andUnwanted Noise!

Here is an antenna with the unique ability todiscriminate between the desired signal andunwanted noise! A complete absence of minorlobes and an extremely high front to backratio are characteristics of these antennas.This is made possible by the development ofthe Free Space Standing Wave MagneticDrive Antenna system (F.S.M.). The out-standing electrical qualities, combined withthe simplified mechanical construction of thissystem yields a total performance packageunparalleled in today's market. 4 models, 60 -

inch to 180 -inch boom, all modestly priced.

UNEXCELLED!UHF - VHF - FM - COLOR

INVESTIGATE NOW!

4A EkeeteWeef Igoe.Manufacturers of the TARGET ANTENNA

204 West Florence StreetToledo, Ohio 43605

TECHNICAL DIGEST

Operate receiver and adjust the HV as instructed in theKC manual. The marking (or lack of marking) on the HVshield determines if the HV requires adjustment.

Amplifier Models T20/30 and T60/112-0n/Off 'Pop' NoiseIf there is a "pop" in the speaker when the amplifier

is switched on or off, the noise can be eliminated as follows:Place a 0.047µf 600v capacitor (Cat. No. EA26X10 or

Primary Secondary

Blk-Red

B1 k-Wh

600V

Red-Wh

Red-Yel

Red

Yel

B1 k

equivalent) across the primary winding of the amplifierpower transformer.

The addition of this 0.047 capacitor will greatly reducethe amplitude of the "pop." Late production amplifiershad this capacitor installed at the factory.

MAGNAVOXRecord Player Motor Pulley Adapters for 50Hz Operation

From time to time we have requests on how a Magna-vox record player can be modified to operate in areaswhere only a 50Hz power source is available. Most recentrecord players can be adapted to provide proper turntablespeed on a 50Hz supply by installation of a motor pulleyadapter which fits over the existing pulley on the motor.These motor pulley adapters are available from your"Magna -Par" parts depot. Here's a list of the adapters andthe record players on which they can be used.

Record player model numbersW603-01 through W603-05, W603-07 &W603-08 (using non -synchronous4 coil, 4 pole type motor) 170573-1

W603 (all versions except those listedabove) and W607 all versions (usingnon -synchronous 2 coil, 4 pole motor) 170574-1

W604, W620, W621, W622 all versions(using synchronous 4 coil, 4 pole motor) 170572-1

W615 all versions except W615-06,W615-07, W615-08 & W615-15 523711-5

Use 50Hz pulley

W617-03 only 52640(VM Part No.)

*W615-06, 07, 08 & 15 versions use a motor with an acoverwind for power to the amplifier and cannot beadapted to 50Hz operation.



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ELECTRONICTECHNICIAN

AUGUST 1967

The State ofSolid -State The Fairchild µA702A IC (in the foreground)

replaces the components shown out of focusin the background.

Solid-state technology surges upward to ultimate levels with microintegrated 'chips'

TEKLABREPORT

For many years electron tubeshave provided the only practical de-tectors and amplifiers. Until tran-sistors were developed, electronicequipment manufacturers dependedentirely on electron tubes. But it hasbeen obvious for some time that thetrend has turned toward solid-stateelectronic circuitry and very few"crystal-ballers" would even hazarda guess regarding the "end of de-velopments" in this area.

Transistors and solid-state diodeshave largely replaced tubes inradios, TVs, hearing aids, digitalcomputers, test instruments and awide variety of industrial electronicproducts.

Semiconductors-and especiallymicrointegrated packages-are re-ducing the size and weight of mostelectronic equipment used in thehome, in industry and in space ex-ploration.

During the first quarter of 1967,for example, sales of receiving tubesto original electronic manufacturers(OEMs) reached 59 million units-a decline of 17.5 percent from

sales of 72 million units during thesame period in 1966.

Total receiving tube sales werealso off 14.5 percent-at 95 mil-lion units-during the first threemonths of this year.

Declines were shown in other re-ceiving tube market areas. Salesfor renewal purposes decreased 9.8percent to reach 27 million unitsand direct sales to the governmentwere down 9.3 percent.

Some reasons why transistorshave many advantages over tubesate as follows:

1. "Small -signal" transistors areabout the size of an eraser on theend of a pencil and take up lessspace than tubes. Power transistorsare about the size of a quarter.

2. Power consumption is small.Transistors and solid-state diodesdo not require filaments. Theirvoltage needs are only a fraction oftube requirements. When used inportable equipment the units aresmaller and lighter in weight. Op-erating costs are lower. Less heatis generated in most applications.

AUGUST 1967 39

Solid -State . . .

3. No warm-up time is required.Solid-state equipment operates in-stantly when switched on.

4. Solid-state construction in asingle compact unit eliminates mov-ing or floating parts making themrugged when used in portable equip-ment.

5. Transistors have a longer lifeexpectancy and can be easily water-proofed with a plastic shell whichallows them to be operated in dampenvironments and even under water.

6. Transistors can provide moreflexibility in circuit designs andcircuits are frequently more simplethan tube circuits-requiring fewercomponents.

Although the basic troubleshoot-ing approach to solid-state circuitsis the same as with electron tubecircuits, the specific procedures re-quire entirely different techniques.Solid-state circuits must not be com-pared with electron tube circuits-we must think solid-state!

More care must be exercisedwhen servicing solid-state circuits toprevent additional problems becauseof careless application of test in-struments-especially when usingmetal probes. A momentary shortor overload can destroy a transistoror other component in the circuit.

As in tube circuits, the over-alltroubleshooting approach is "logicaldeduction through knowledge ofcircuit operation." And techniciansmust apply their knowledge of solid-state circuit operation to masterthese circuits successfully.

Solid -State Test Instruments

Solid-state VTVMs, with self-contained power supplies and hav-ing a 1.5v full scale, are now beingmanufactured. Small potentials as

POWER

of,

yire4-<%2Z

FM -STEREOMULTIPLEX GENERATORM

C N.Ahht1

AUDIO

RW1110

A.INLJAYOl

MONO.7 KC

AUDIO COMPOSITE

001.01

s,1110 101(C

Hickok FM/stereo multiplex generator model 727.

LEFT SIGNAL

Not.

el

PEAT MOT smut

6 OE o[HANNELIZO

OF"'

OIr .,E4.0NO

...

oh

Sencore's Mr11 solid-state stereo generator.

low as 0.025v can be measured withthese instruments. This feature isextremely useful when measuringthe base -to -emitter bias-rangingfrom 0.1 to 0.6v with germaniumand silicon transistors-when trou-bleshooting transistorized circuits.These meters are protected againstdamage from accidental overload.The high input impedance of theseVTVMs prevent circuit loadingwhich may cause damage to a tran-sistor or other circuit component.

Solid-state signal -injection and-tracer instruments have also beendesigned to check transistor radios.

RF

001pul

Servicing solid-state equipmentby signal -tracing and signal -injectionis the most effective way to isolatedefective stages in solid-state equip-ment. With this type of test instru-ment, either the signal -tracing orsignal -injection method can be used.When signal -tracing, the instrumentis set up as a receiver. Signals inthe RF, IF and audio stages arepicked up with the probe, amplified,then converted into an audiblesignal which is monitored by thetest instrument's speaker.

When signal -injection methodsare used, the tester is set up as an


ri3j42r 1241 soup

1111111011 COLOR 4110

1 IG PATTIIIN

Ammummeinimplr-

138K's solid-state color generator model 1242.

Amphenol's solid-state millivolt "Commander," model 870.

RF or audio generator. Signals areinjected and the radio's speaker isused as an indicator. When signal -tracing, the usual method is to beginwith the defective set's RF stageand work toward the speaker. Withsignal -injection, the reverse proce-dure is used-starting at the speakerand working backward toward theRF stage.

FM/stereo broadcasting and re-ceiving is rapidly gaining public in-terest. Standard FM broadcastingwill no longer satisfy the millions ofpeople who have been educated tofine music and voice reproduction.

The best receivers and associatedequipment cannot give proper re-sponse if the components are notproperly balanced and aligned.

Rules and regulations set forthby the FCC require complex re-ceiver circuitry which is difficult toservice without special test instru-ments. But special solid-state testinstruments have also been designedto cope with these problems.

A light -weight, portable, self-con-tained power supply FM/multiplexgenerator can be carried into thehome and it generates a completecomposite FM/multiplex signal in

accordance with FCC specifications.For more information on these gen-erators refer to the article series,"Using Audio Test and AlignmentInstruments," which began in theMarch 1967 issue of ELECTRONICTECENICIAN.

Solid-state test instruments fulfillthe need for lightweight portabletest instruments.

IC and FET Circuits

Many transistor tuners and receiv-ers on the market today are subjectto cross modulation-powerful sta-tions can appear at several pointson the dial-interfering with othersignals which listeners want to re-ceive. Resistance to cross -modula-tion is an inherent failing of ordinarytransistor circuits. One solution tothis problem is to use regular tubesor nuvistors in the front end of anotherwise all -solid-state tuner. Thishybrid design works well initially,but is said to defeat its own purposeeventually, since tubes generatedrift -producing heat and fail morequickly than transistors. One manu-facturer claims to have solved thisproblem by using field-effect tran-sistors (FETs). For detailed infor-mation on FET circuitry, refer tothe article, "Semiconductors fromA to Z," which has been runningin ET since August 1966.

The first FETs made are reportedto have sold for about $30 eachand were considered a curiosity bydesign engineers. After a short time,however, useful applications weredeveloped for special military equip-ment. FETs had a very high inputimpedance but circuit designers whohad experience only with transistorsfound themselves attempting toapply unfamiliar electron tubetechniques.

Today, the price of FETs hasdropped to only a few dollars.Various types of field-effect transis-tors are now available, includinginsulated -gate, metal oxide andeven thin-film types. A number ofFET FM receiver front ends havebeen developed and the circuit ofone of these is shown in Fig. 1.

Integrated circuits are now beingused more widely. They can be ap-plied to regenerate the 3.58MHzsubcarrier in color TV sets. At

AUGUST 1967 41

Fig. 1-Diagram of theScott FM tuner front-end

which employs threeFET and one conventional

transistor.

Fig. 2-Schematic of voltage -controlled crystal oscillator using theFairchild µA703C IC.

present, three methods are used:(1) The voltage controlled crystaloscillator in an automatic phase con-trol (APC) loop, (2) The injection -locked crystal oscillator, (3) Thenarrow bandpass crystal ringingcircuit.

Two of the aforementionedmethods are shown in Fig. 2 andFig. 3. The IC and associatedcircuitry for a voltage controlledcrystal oscillator is shown in Fig. 2.The IC and associated circuitry foran injection -locked crystal oscillatorthat is basically similar to the volt-age -controlled oscillator is shown inFig. 3. Except for the smaller ratioof Cl and C2-allowing for addi-tional voltage drop of the bursttransformer impedance in the feed-back loop-the output tuned circuitis the same.

SIO

T T"CO

..0

MIS

LOW OUT

NIGH IN

6 mA

COLOR BURSTTRANSFORMER

C3 NI

7.2k

LOW IN

-

0.01

3579 545 4F1:-Il

=29 ph

0.01

R,2.74

CI75

C2 mim470 I

Fig. 3-Schematic of injection -locked crystal oscillator using the Fair-child µA703C IC.

Solid -State Home EntertainmentEquipment

Most manufacturers today are ex-tending their lines of equipmentcontaining transistors, microelec-tronic and integrated circuits. Thisincludes color and B/W TV, con-sole stereo, portable phonographs,tape recorders and tape players.

One company has a color TV anda color TV/radio/ phono combina-tion with an IC in the picture ampli-fier circuits.

A console stereophonic Hi Fiphono has an IC in its FM limiterstage.

A new remote -control transmitterhas an integrated circuit.

The same company claims tohave 85 percent of its radio linefully solid-state.

Another company has alreadyintroduced a line of solid-state colorTV receivers-believed to be thefirst sets of their kind to be mar-keted in this country. These re-ceivers also employ ICs.

As previously made clear, solid-state transistor products operatecooler than electron tube versions-an advantage which extends the lifepotential of components andpromises greater reliability overtube sets.

ET'S TEKLAB is extending its in-vestigation into solid-state trou-bleshooting and repair techniques.It is recommended that all service -dealers and technicians reviewprevious articles on this subject andfollow closely forthcoming articleswhich deal with solid-state develop-ments and servicing methods.


UNDERSTANDINGMODERN AGC CIRCUITS

Learn some of the 'service -secrets' that separate the 'men' from the 'boys'

The fourth article of this series(ELECTRONIC TECHNICIAN, July1967) explored some general andparticular considerations concern-ing troubleshooting modern keyedAGC circuits-tube and solid-state.

It was also pointed out that aspecial "viewpoint" was necessarybefore these circuits could be re-paired rapidly enough to satisfypresent-day TV owner demandsand meet competitive standards nowbeing established by an increasingnumber of alert and progressiveservice -dealers.

Perhaps it would be helpful torepeat: use your intelligence (it'salso called common sense) whenapproaching any service problem-and this includes modern AGC serv-ice problems.

The Modus OperandiIn the previous article it was

made clear that an AGC system isbut cne circuit in a closed -loop"chain" composed of individual,interdependent, interactive links. Itwas also indicated that the entireloop must be "seen" and consideredin -total when diagnosing trouble -symptoms as revealed by the CRTscreen or the speaker. But we didnot suggest that the total loop beconsidered as one solid, elaborate,complicated and formidable mazewhich, according to the views ofsome, was designed especially by theengineers to frustrate hard-workingtechnicians.

The modus operandi of trouble-shooting AGC circuits-the mannerin which you work-is the same forall types of electronic circuitry: in

most cases it involves common-sensetechniques and proper test instru-ments. To state it another way, itrequires knowledge of the equipmentand logical thinking. It's as simpleas finding a needle in a hay-stack-by using a hundred -thousand -gausselectromagnet!

As every skilled technican knows,three of the five inherent humansenses-sight, touch and smell-can reveal clues that lead directlyto a rapid solution to most elec-tronic circuit problems.

Observe the "old pro" in actionat the service bench for a moment.He has just placed a chassis on itssade, with the "guts" showing andthe set is switched on. In a cool,relaxed and confident manner, hepokes his nose close to the chassisinnards and literally "sniffs around"-like a bird-dog circling throughquail cover. He looks closely fortell -tale charred or broken or heat -discolored resistors. He cautiouslyfeels a few resistors or power tran-sistors with a forefinger.

When he locates one or moreresistors that are obviously burnedopen, discolored or overheating, helooks for the cause: a shorting tubeor defective transistor, a leakingcapacitor or possibly some othercause and he may briefly refer to aschematic of the equipment. At anyrate, the fault is quickly confirmedby a VOM, VTVM, a scope, anin -circuit transistor or capacitortester. He may replace one or moredefective components and the job isdone. Skilled bench technicians fre-quently troubleshoot and repair avery large percentage of ailing TV

AUGUST 1967 43

ANT.4, ---

TUNERRF

DEL AYNET.

-OwVIDEO

IF

KEYER

H VIDEODET.

VIDEOAMP

HOR.OUTPUTTRANS

HOR.SWEEP

Fig. 1-The loop in which the AGC keyer unit is but one link in an interdependent chain.

sets by using these simple methods.But a substantial number of prob-

lems do not yield to these trouble-shooting techniques. These problemsusually arise because of subtle shiftsin circuit -component tolerances-sudden changes in resistance andcapacitor values, small leakages incapacitors, intermittently defectivetubes, transistors, capacitors, resis-tors, coils and solder connections.These are the problems that oftenbecome time consuming for unskilledand inexperienced technicians-these are the "hair -pulling" prob-lems that separate the "men" fromthe "boys" in the troubleshootingarea of electronics.

As repeatedly stated in previousarticles, the first step in servicingany equipment is to localize theproblem to one specific area of theequipment-one particular circuit.Since the AGC system is one "link"in a closed -loop "chain" our firststep here is to determine if theproblem is in the AGC link orsome other link in this loop (seeFig. 1).

In tube circuits particularly, westated that the best way to determinewhether or not the fault is in theAGC circuit or elsewhere, is to sub-stitute a variable bias supply. And

this also holds true in most caseswith solid-state circuits. But remem-ber that "forward-AGC" is fre-quently employed in solid-state AGCcircuitry and, depending on the tran-sistors and circuitry used, the polar-ity of the AGC voltage may beeither positive or negative with re-spect to ground. If you are not up-to-date on your transistor theory,study the comprehensive article,"Semiconductors from A to Z,"which has been running in ELEC-TRONIC TECHNICIAN for more thana year.

Now let's stop the philosophizingand generalizing, get our dogs beforethe guns, and see what specific gamewe can flush up.

To the PointThe schematic in Fig. 2 shows

a forward-AGC transistor circuitwhich provides a positive voltageon the AGC buss. This circuit isused in Motorola's TS458 chassis.

The following checks on the AGCsystem are recommended to deter-mine if the fault is in the system orelsewhere:

1. Set the tuner between channels(no signal). Measure the voltageat test -point (TP) "A." It shouldbe 2.5v. With the tuner set on a

medium -strength station, the poten-tial should be close to 4.5v.

2. Measure the voltage at TP "B."It should be about 33v with no signaland approximately 15v with a me-dium -strength station tuned in.

3. Measure the voltage at TP "C."It should be near 3.2v with no signaland about 5v with a strong signal.It should be noted, however, thatthe voltage at TP "C" will varywith the setting of the AGC delaycontrol, R405.

If the voltages are not withinthe aforementioned tolerances underthe stated conditions, the next moveis to determine if the AGC gatetransistor (Q11) can function prop-erly-can be "keyed" on and off:

To turn Q11 off, short its emitterand base. The voltages at TP "A,""B" and "C" should then be thesame as they were when the tunerwas set between channels (nosignal) as previously stated in steps1, 2 and 3-2.5, 33 and 3.2v re-spectively.

To turn Q11 on, short the emitterand base of the 1st video amplifier,04. The voltages at TP "A," "B"and "C" should now read 6, 2 and13v respectively-about the same aswhen a very strong signal is beingreceived.


+ 33V

RF

AGC

R404+ 33V o

AGC R405DELAY

WITH 3K 186

STOP

14V PP V

04VIDEO AMP

TO

FROM NOISE

GATE

C401

R402

025AGC

DELAY

R121

R403 0406120K 220

+ 75V

C109

E401

011

C4Of

AGC

GATE

2MF

CI1ST VIDEO

IF

02250 VIDEO

IF

R102 8106

2.26 T. P. 2.26

R101

2.7K

40V PP H

I. PULSE9. COIL

ON

FLYBACK

T.P.

0403

.0015

R409

3.9K

R107.8W

3012

336

AGO

AMPR412

470

R419 R413

.9AM MN'47K. 126

Fig. 2-Keyed AGC system in Motorola's transistorized TS458 chassis.

If these steps check out OK asindicated, you will then know thatthe entire AGC network is function-ing properly and your problem-horizontal bending and overloading,for example-is probably beingcaused by a fault in the IF section,the video detector or the video out-put circuit.

We should remind ourselves atthis point of a few important func-tional details regarding this partic-ular keyed AGC circuit. A thoroughunderstanding of how it functionswill make troubleshooting mucheasier.

When the tuner is set betweenchannels (no signal), the AGC gate(Q11) is reverse biased by the lowcollector voltage of the 1st videoamplifier (Q4). This transistor(Q4) produces a large voltage dropacross R403 which causes the baseof Q11 to be negative with respectto its emitter-thus reverse biasingits emitter/base junction and pre-venting conduction.

When a TV signal is tuned in,the diode video detector (not shownin the schematic) feeds a negative -going video signal, plus a certainamount of dc, to the base of Q4which drives it toward cutoff. Thisdecreases Q4's collector current and

0+ 33V

the voltage drop across R403 alsodecreases. This will cause the volt-age on the base of 011 to becomemore positive with respect to itsemitter. This action will forward -bias Q11 and allow collector cur-rent to flow-if we apply a positivevoltage to its collector of sufficientamplitude to override the 33v on itsemitter. This override voltage isobtained from a small winding onthe flyback transformer.

Note that the 40v P -P positive -going flyback pulse is fed to theanode of the diode, E401, forward -biasing it and turning it on. Thisvoltage will cause Q11 to conduct,in turn charging C402 as follows:

Electron -current will flow fromthe plus side of C402 through limit-ing resistor R406 to the emitter ofQ11, then through E401, the hori-zontal pulse coil and to the nega-tive side of C402. This capacitorcharges to a negative value whichis proportional to the amplitude ofthe horizontal sync pulses of thereceived signal.

When the horizontal pulse is notpresent, C402 starts to dischargebut the negative voltage on it re-verse -biases E401. This preventsC402 from discharging through thecollector -to -base junction of Q11

forcing it to discharge partially ina negative -to -positive directionthrough R410 and R413.

Note the time cycle of C402 andassociated components. The capaci-tor charges rapidly through a rela-tively small resistance but dischargesonly partly through a relatively largeresistance. The net result of thisaction creates a negative charge onC402 which makes TP "B" nega-tive with respect to the 33v supply.The swing of this negative voltageis directly proportional to the ampli-tude of the horizontal sync pulseswhich appear at the base of the AGCgate, Q11, at a given instant.

But wait! We observe that thedesign of the IF section requires aplus bias voltage on its 1st and 2ndvideo stages so the forward -biasbetween base -and -emitter can bevaried to increase and decrease thecurrent flow in their collector cir-cuits (decrease and increase thecollector voltage) to control thesignal strength through forward-AGC-action.

The AGC amplifier (Q11), aPNP transistor connected as a com-mon -emitter, inverts the voltage180deg and makes it positive. Thisadditional positive voltage, togetherwith the 2.25v which already ap-pears at TP "A," is the AGC voltagewhich is coupled to the bases ofQ1 and 02 through current -limitingresistors R102 and R106.

The AGC delay transistor circuit,Q25, is designed to turn on andapply RF AGC just before signaloverload occurs in the tuner.

The proper way to adjust theRF AGC control (R405) is asfollows:

1. Set the control fully clock-wise-giving maximum RF AGCdelay.

2. Tune in a medium strengthsignal.

3. Turn the AGC delay controlslowly counterclockwise (CCW)until noise is just visible in the pic-ture. Then turn the control clock-wise (CW) until the noise on thescreen just disappears.

Forthcoming articles will dealwith additional troubleshootingproblems in various types of AGCcircuits-both electron tube andsolid-state.

AUGUST 1967 45

SOLID-STATETV SERVICING

THE EASY WAY

Fig. 1-Schematicof the G -E "TA"

power supply.

1401C402MOO

C401- 300041

20V

120V-rMff:: \ EXTERNAL BATTERY60, k

RI40002

Don't let the 'littlemonsters' scare you

120V AC LINE +15V. DC110V AC LINE .. 1311 DCI35V AC LINE +17V DC

R404220bN

02051066

ERROR AMP

021T1115

REGULATOR

R4072200

+12V

R403 OPM130 4- 36

REGULATOR

06

R405

000

R40647

X ,sn..022A

Fig. 2-The "old pro" uses a variable ac powersupply to bring up the line voltage slowlywhen checking for shorts and overloads.

II It has been made repeatedlyclear that you cannot survive in thisbusiness unless you have a thoroughknowledge of basic solid-state circuittheory. Many articles - coveringvarious aspects of this subject -have already appeared in thesepages. Practical servicing techniqueshave been detailed. But forthcomingarticles will explore these areas evenmore thoroughly. This article willdeal entirely with practical trouble-shooting procedures and, althoughconcentrating on the G -E "TA"chassis, the fundamental servicingtechniques can be applied to allcomparable solid-state circuitry.

Practical Troubleshooting

The "TA" chassis first came toour bench "dead" - no raster, noaudio. You may or may not knowthat the "TA" chassis has a line-operated 12v, regulated dc powersupply (see Fig. 1). You wouldnormally check this supply firstwhen confronted with the previouslymentioned symptoms. And you'll

Fig. 3-Penknife is used to cutcircuit foil and isolateoverloaded section of set.

Fig. 4-024 transistor and Y254 diode arelifted from heat sink when checkingfor shorts in the B+ line.


find it helpful to use a variable117vac supply.

Plug the set into the variable acsupply output. Check the ac linefuse, F401 (Fig. 1) and the outputfuse, F402. If the ac input fuse isblown, replace it. And if the dcoutput fuse is blown, replace it also.

Now adjust the variable -voltagetransformer to bring the ac line po-tential slowly up to 120v while usingthe old "see, feel and smell" benchtechnician's technique. At the sametime, monitor the 12v B+ line toground with a VOM. If you havelittle or no voltage, switch the setoff.

Disconnect the B+ loads from thepower supply (one at a time) -switching the set on after each loadhas been disconnected. Each loadcan be disconnected easily by cuttingthe circuit foil (see Fig. 3) with asharp penknife, razor blade, etc.Observe if the B+ rises to 12v. Ifthe B+ is still not correct when allloads have been disconnected, thenthe trouble is either in the voltageregulator or the power supply.

Now try to obtain correct B+voltage by adjusting R405 (see Fig.1). If this does no good, check Q20,the error amplifier and 021, theregulator transistor on an in -circuittransistor tester. If they check OK,all you have left is the zener diode,Y403. If you don't have a zenerdiode tester, substitute the suspectedzener with a known -good one.

These regulator circuits can havea very fast control response - fastenough, in fact, to remove 60 or120Hz ripple. This regulator actslike a large filter capacitor and helpssmooth the B+ voltage.

Of course, you can vary this ap-proach in a number of ways. Sup-pose, for example, the dc voltageat the regulator output is lower thannormal but not out altogether. Yoususpect that heavier -than -normalcurrent is being drawn by one ofthe loads. In this case, remove thefast -blow 1.5a fuse (F402 shown inFig. 1) and replace it temporarilywith a 0.5a similar -type fast -blowfuse. Open the line at "A." Inserta 1 a full-scale meter in the line.Switch the set on. If the meter readsmuch more than 430ma, you willhave some idea of what your prob-

lem is. Of course, you could openlines at various points in the supply,including individual output loadpoints, measuring the current drawnat each point and probably comeup with all the information you needto pinpoint the trouble. But be care-ful you do not burn out the millia-meter - make initial checks on thehighest scale.

Because Q24, the horizontal out-put transistor, Y254, the damperdiode and Q19, the vertical outputtransistor, have been known toshort, it would be wise to lift andisolate these from their heat -sinkmounts when checking for a loss orfor extremely low B+ voltage (seeFig. 4).

Precautions

We believe it would be advisableat this point to mention some pre-cautions that should be taken beforeattempting to troubleshoot this orsimilar -type equipment.

To avoid excessive transient volt-ages while servicing any part of theset, use a zener diode connectedfrom the emitter to the collector ofQ24, the horizontal output transis-tor. A zener can be used on anysolid-state circuit where expensivetransistors are involved.

Always use a low -wattage de -soldering iron and heat -sink clipswhen removing or installing transis-tors (see Fig. 5). And the equipmentshould be switched off before probesor leads from test instruments areconnected into any circuit. Alsomake sure that all test leads are atground potential and momentarilyshort each test probe to chassisground before making contact withthe test point. Excessive transientvoltage will quickly destroy solid-state components. An ohmmetercan be used for checking the forwardand reverse resistance of semicon-ductors. But make sure that no morethan 1.5v appears across your meterprobes.

Horizontal Section

If the screen of this set does notlight or the raster size is inadequate,check the 12v B+ first. If the B+checks OK, then check the voltage

at test -point A. It should be 90v.If so, this usually means the out-put transistor is operating properly.Use your scope to check for properoperation of the horizontal sweepsection and if this checks out butthe 90v source is not correct, dis-connect various loads from this sup-ply until correct voltage appears -isolating the defective area. Alsocheck diode Y259.

Now check the amplitude, fre-quency and shape of the waveformof the horizontal output drive signal.The emitter and base leads are dis-connected for this check and a 1052resistor is connected between theseleads. The scope is then connectedacross this resistor and a 4 to 6vP -P drive voltage, at the horizontalsweep rate, should appear at thispoint. If the drive signal is correct,check the components in the hori-zontal output circuit. An incorrectdrive signal would point to troublein the buffer or oscillator stage. Aslight decrease in horizontal sweepand striations (see Fig. 6) indicatethat damper diode (Y254) has

Fig. S-A desoldering iron and heat -sink clips are used to removeand replace transistors.

Fig. 6-This symptom wascaused by anopen damper diode.

AUGUST 1967 47

Fig. 9-Schematic ofthe IF and AGC sections

of G -E's "TA" chassis. $Z18°08

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opened. Unlike tube sets, this TVchassis will operate under these con-ditions but the B+ current will in-crease about 100ma if Y254 opens.

A scope is a must for checkingvertical and horizontal sweep cir-cuits in solid-state TV equipment.All transistors in these circuits aredriven by shaped pulses.

Raster Good, Videoand Audio Absent

A systematic signal injection ap-proach is recommended to pinpointtroubles in solid-state TV equip-ment. To determine if the aforemen-tioned symptoms are caused by adefective tuner or IF component,check B+ and AGC to the tuner.Inject a modulated IF signal at theIF link. If the IF test signal passesthrough the video IF amplifier, thenthe defect is probably in the tuner.And the RF stage in the tuner maybecome inoperative because of toomuch or too little AGC voltage.

Fig. 7-Close-up view of miniaturizedVHF tuner frequently used incompact solid-state TVs.

569

FA502 3.8V2.IV

C21/8

15Y

.64V 815066V 4700

014530m,6V I

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3.2V CHITO Yi°-.1251 4.49 51AGC061

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TO7251

Measure the voltages of 01, Q2and Q3 in the tuner. Check thetransistors on an in -circuit transis-tor tester. But you'll need eagleeyes, the steady hands of a brainsurgeon and the patience of Job torepair these tuners (see Fig. 7).

The ability of the tuner to passRF is determined by injecting anRF sweep signal into the input of theRF stage. If the RF signal does notpass through the tuner, check theoscillator circuit. One easy way tocheck the oscillator is to measurethe transistor's emitter and basevoltages while rotating the fine tun-ing control. If the voltage varies,the oscillator is operating.

If you find the VHF tuner isoperating properly, check out thevideo IF section. Inject a 45MHzsignal (see Fig. 8). The first twostages of this IF strip are controlledby forward-AGC. Check the AGCvoltage at this point. If it is notcorrect, use a bias box to apply 3vpositive to test point II of the AGC

Fig. 8-Using the "analyst- toisolate trouble bysignal injection.

81221 - C129T 1000

01321000

(see Fig. 9). If the test signalnow appears on the screen, then thefault is in the AGC circuit.

The symptoms that appear on theCRT screen of a defective set cansometimes be misleading. The pic-ture shown in Fig. 10, for example,would lead most technicians tosuspect AGC or sync troubles. Thissymptom, however, was caused byan open 1st IF transistor, Q4.

Continue injecting a test signalinto the IF strip until the test pat-tern appears on the screen - righton up to the video detector. Thenswitch the "analyst" to a video sig-nal and trace right up to the con-trol grid of the CRT.

AGC and Sync Sections

The AGC circuits of this set arecomposed of a keyer stage, followedby a dc amplifier that controls thegain of the 1st and 2nd IF stages.A second dc amplifier controls the

continued on page 80

lig. 10-This symptom looked likeAGC or sync trouble but was caused byan open 1st IF transistor, Q4.


Part three of a

TEKLABREPORT

test instrument series

Fig. 1-The basic makeupof a squarewave withall elements in phase.

Using AudioTest and Alignment InstrumentsCombine a sine/squarewave generator with a good scope for faster and more efficient servicing

Two previous articles in thisseries covered multiplex signal gen-erator applications.

Sine/squarewave generators canalso be used effectively to locatedefective circuits in medium andwideband amplifiers. The square -wave generator, in conjunction withyour scope, can be a valuable instru-ment combination for troubleshoot-ing audio amplifiers.

It should be pointed out here thatthe price you would pay for a sine/squarewave generator depends onthe amount of audio service you doand how much you can afford tospend. A rule -of -thumb here indi-cates that you should spend as muchas you can afford.

The only requirements that mustbe met by the sine/squarewave gen-erator is good rise time (about

0.5p.sec or better) and a frequencyvariable between 60Hz and 25kHz.Generators in this category are alsoavailable in kit form. Most genera-tors cover the entire frequencyrange (both sine and squarewave)from 20Hz to 100 or 200kHz infour or five bands.

As most of us know, a theoreti-cally perfect squarewave is made upof an infinite series of odd harmonicsinewaves (1st, 3rd, 5th, etc.).

The basic makeup of a square -wave is shown in Fig. 1. All odd -numbered harmonics are shown inthe in -phase relationship-eachsinewave cycle. To develop thesquarewave as shown it is necessaryto draw a number of vertical linesthrough the squarewave and to add,algebraically (observing polarity),the magnitudes of the sinewaves

along this vertical line. For simplic-ity, we will only consider harmoniccontent to the 9th harmonic.

At "Al," for example, we havealgebraically added the fundamen-tal, 3rd, 5th, 7th and 9th harmonicswith the resultant summation ofwave magnitudes along a largenumber of vertical "check" lines toobta,n the squarewave.

When a squarewave is sentthrough an amplifier it is equal tousing a number of test frequenciessimultaneously. If the resultantsquarewave trace on the scope is notmisformed in any respect at variousfrequencies, then we can say theamplifier response is flat over a widerange of frequencies. If the square -wave frequency is 100Hz, the ampli-fier response is good up to about900Hz to 1.1kHz.

AUGUST 1967 49

iaco

0co

100 Hz kHz 10 kHz 100 kHz

Ng. 2-Chart showing frequency response of amplifier.

Test Setup

Although the test setup shownon the previous page does not pic-ture it, the Precision model E310sine/squarewave generator wasused in these tests. It should alsobe noted that the output impedancesof the generator and amplifier mustbe matched. Keep leads short. Al-low the amplifier and test instru-ments to warm for about 15min.

1. Set the generator controls andswitches as follows:WAVEFORM switch to SINE

RANGE switch to 50-600OUTPUT LEVEL control to ap-

proximately 50OUTPUT to XI2. Connect the ground binding

post of the generator to the ampli-fier ground-the other output postto the amplifier input.

3. The output of the amplifiermay be measured with any highimpedance ac measuring instrumentwith flat response over the antici-pated range. A VTVM equippedwith ac measuring facilities may beused; however, a scope equippedwith a low capacity probe is one ofthe most useful high impedance in -

Fig. 4-Curveobtained by de

pressing the lowfrequency com-ponents in the

squarewave.

A

100Hz

SQUARE

WAVE

I kHz

SQUARE

WAVE

B

Fig. 3-Squarewave patterns at various frequencies.

struments available to technicians.We will then assume that a scope isconnected directly across the ampli-fier output (the speaker voice coilor to the plate circuit of the lastamplifier).

4. Set the generator tuning dialto 60Hz, for example, and adjustthe gain of the scope and the outputof the generator to obtain a goodsized sine pattern on the scopescreen. Keep in mind that the gen-erator output should be maintainedat minimum-consistent with oper-ating conditions-to minimize thepossibility of overloading the ampli-fier and introducing false indicationsof distortion.

Use the OUTPUT LEVEL control toset the maximum output desiredfrom the generator and then use theOUTPUT switch to reduce the genera-tor output.

5. Note the total height of thesine pattern on the scope screen bycounting the number of verticalsquares it occupies on the scope'scalibrated crosshatch mask (P -Pmeasurement).

6. Without touching any othercontrols or switches, merely rotatethe tuning dial of the generator to

200 and note the difference, if any,in the height of the sine pattern onthe scope.

7. Repeat the procedure for asmany frequency points as requiredto display the curvature of theamplifier response, using the P -Psinewave amplitude readings as indi-cated on the scope's cross hatchmask.

Squarewave GeneratorAmplifier Checks

Amplifier distortion can be classi-fied into the following three cate-gories:

Frequency Distortion. This refersto the change from normal ampli-tude of a component of a complexwaveform. Resonant networks orselective filters created by a combi-nation of reactive components(resonant networks and selectivefilters in amplifier circuits) willcreate peaks or dips in an otherwiseflat frequency response curve.

Non-linear Distortion. This refersto a change in waveshape producedby application of the waveshape tonon-linear components or elementssuch as electron tubes, an iron coretransformer and in an extreme case,


a deliberate non-linear circuit suchas a clipper network.

Delay or Phase Distortion. Thisis distortion produced by a phaseshift between one or more compo-nents of a complex waveform.

In actual practice, a reduction inamplitude of a squarewave compo-nent (sinusoidal harmonic) isusually caused by a frequency selec-tive network which includes capac-ity, inductance or both. T h epresence of C or L introduces a dif-ference in phase angle betweencomponents-creating phase distor-tion, or delay distortion.

In squarewave testing of practicalcircuitry, we will usually find thatthe distorted squarewave includes acombination of amplitude and phasedistortion clues.

If we apply squarewaves to atypical wideband amplifier, we findthe check accurately reveals manydistortion characteristics of thecircuit.

As indicated in Fig. 2, the ampli-fier response was poor at low fre-quencies along with overcompen-sated high frequency boost.

A 100Hz squarewave applied tothe input of this amplifier will ap-

pear as in Fig. 3A. This illustrationindicates satisfactory medium fre-quency response (approx. 1kHz to2kH,z) but shows poor low fre-quency response. In Fig. 3B, a1 kHz squarewave was applied tothe input of the same amplifier.This figure displays good frequencyresponse in the region of 1 kHz to4kHz but clearly reveals the over-compensation at the higher 10kHzregion by the sharp rise at the topof the leading edge of the square -wave.

As a rule of thumb, it can besafely said that a squarewave canbe used to reveal response andphase relationships up to the 15thor 20th odd harmonic or up to ap-proximately 40 times the square -wave fundamental. Wide bandcircuitry will require at least a two -frequency check to analyze thecomplete spectrum properly. In thecase illustrated in Fig. 2, a 100Hzsquarewave will encompass compo-nents up to about 4kHz. To analyzeabove 4kHz and beyond 10kHz a1 kHz squarewave would be satis-factory.

The region between 100Hz and4kHz (Fig. 2) shows a rise from

Fig. 5-Graphicaldevelopment ofa similarly tiltedsquarewave Fx3out of phase(lead).

poor low frequency response to aflattening out from between 1kHzand 4kHz. Therefore we can expectthe higher frequency components inthe 100Hz squarewave will be rel-atively normal in amplitude andphase but the lower frequency com-ponents in this same squarewavewill be strongly modified by thepoor low frequency response of thisamplifier (see Fig. 3A).

If the combination of elementsin this amplifier were such as toonly depress the low frequency com-ponents in the squarewave, a curvesimilar to that shown in Fig. 4would be obtained. Reduction inamplitude of a component as al-ready noted, however, is usuallycaused by a reactive element whichresults, in turn, to a phase shift ofthe component, producing thestrong tilt shown in Fig. 3A. Thegraphical development of a simi-larly tilted squarewave is shown inFig. 5. The tilt is seen to be causedby the strong influence of the phase -shifted 3rd harmonic. It also be-comes evident that very slight shiftsin phase are revealed by tilt in thesquarewave. An up -coming articlewill explore this subject further.

AUGUST 196751

Detecting Phase Shift

Fig. 6-In-phase (or 180deg out of phase) no Fig. 7-Phase shift no overload distortion.overload distortion.

Fig. 8-In phase and overload distort:on. Fig. 9-Phase shift and overload distortion.

A

D

B C

F

G H

. J

Fig. 10 (A)-Frequency distortion (amplitude reduction of low frequency component) no phaseshift. (B)-Low frequency boost (accentuated fundamental). (C)-High frequency loss-No phaseshift. (D)-Low frequency phase shift. (E)-Low frequency loss and phase shift. (F)-High fre-quency loss and low frequency phase shift. (G)-High frequency loss and phase shift. (H)-Dampedoscillation. (I)-Low frequency phase shift (trace thickened by hum -voltage).

1. Set the sine output of thegenerator to the desired frequency.

2. Set the LEVEL control tomaximum position and apply theoutput directly to the vertical platesof a scope.

3. Construct a simple resistivevoltage divider by connecting a 2Kpot across the generator output.Feed the voltage developed acrossthe arm of the pot and ground tothe input of the amplifier beingchecked. (Set the pot for mini-mum voltage consistent with a size -

Jackson Model 605D audio sineisquarewaveoscillator.

JACKSON MODEL 605D

FREQUENCY RANGE:20Hz-200kHz in 4 rangesCALIBRATION ACCURACY:3% or 1Hz whichever comes firstOUTPUT VOLTAGE:Cathode follower, continuously variableSinewave 0 to 5.0 RMS volts, squarewave 20mvto 7.0 P -P

OUTPUT LEVEL CHARACTERISTICS:1db over full rangeHUM LEVEL:Down more than 50db at all output levelsSINEWAVE:Less than 1% distortionSQUARE WAVE RISE TIME:Less than 0.24SQUAREWAVE TILT:5% at 60Hz, less than 1% above 200Hz7SsIE:x

WEIGHT:Vs X 103/4 in.

14 lbPRICE:$144.95


able scope pattern.) The ampli-fier output is fed directly to thehorizontal plates of the scope.The resulting scope waveformwill display an elliptical formif phase distortion exists in theamplifier at the test frequency.The degree of phase shift is ofcourse indicated by the shape of theelliptical pattern. (Top or bottomflattening of the elliptical shapeindicates overloading produced byexcessive input to the amplifier.)If overloading does occur, set thepot to a lower level (see Fig. 6to 9).

Hewlett-Packard Model 200CD wide rangeoscillator.

MODEL 200CDHEWLETT-PACKARDFREQUENCY RANGE:5Hz-600kHz in 5 rangesACCURACY:-±2% including calibration error, warmup,changes caused by aging of components, tubes,etc.DIAL:6in dia calibrated over 300 deg of arc. 85 divi-sions. Total scale length, 78 in.FREQUENCY RESPONSE:-±-1db entire frequency range (reference 1kHz)OUTPUT:160mw (10v) into 600 2 rated load, 20v opencircuitOUTPUT BALANCE:Better than 0.1% at lower frequencies and1% at higher frequenciesINTERNAL IMPEDANCE:600 !!. Output is balanced to ground for zeroattenuation. (May be operated with one sidegrounded if desired.)DISTORTION:0.2% from 20Hz to 200kHz; 0.5% from 5Hzto 20Hz and from 200kHz to 600kHzHUM VOLTAGE:Less than 0.1% of rated output, decreasesas output is attenuatedPOWER:115/230v ±10%, 50Hz-1kHz 90wSIZE:738 x 111/2 x 143/8PRICE:$225

Speaker Checks

The sinewave generator becomesuseful when applied to correct theusual mis-match between speakerand the speaker enclosure itself.

The "boomy" bass response ofcommercial speaker enclosure com-binations can be transformed into asmooth natural response.

A bass reflex speaker systemmay be checked as follows:

1. Connect the variable sineoutput of the generator in serieswith a loon resistor to the speakervoice coil.

Eico Model 377 sine/ squarewave generator.

EICO MODEL 377

FREQUENCY RANGE:Sinewave 20-200kHz in 4 bandsSquarewave 60-50kHz (5% tilt at 60Hz, 5%rounding at 50kHz)CALIBRATION ACCURACY:±3% or 1Hz whichever is greaterFREQUENCY RESPONSE:-±-1.5db, 60-150kHzOUTPUT VOLTAGE:10v across 1K rated load (100mw), drops8v across 500 1!, rises to 14v across 10KhigherDISTORTION:Less than 1%HUM:Less than 0.4% of rated outputSIZE:(HWD) 71/8 x 111/a X 75/8 in.WEIGHT:13 lbPRICE:Kit $39.95 Wired $54.95

toOr

2. Connect an ac voltmeter orscope across the speaker voice coil.

3. Determine the low frequencyresonant peaks in the system bynoting peak voltmeter readings.The frequency of these peaks willvary with the size of the speakerand cabinet but should occur inthe region between 40 and 150Hz.In a properly tuned system the twopeaks should be rather broad andof approximately the same ampli-tude. If one of the peaks isgreater than the other, try damp-ing the port with additional layersof grill cloth.

Precision Model E.310 sine/ squarewave signalgenerator.

PRECISION MODEL E-310

FREQJENCY RANGE:Sine and squarewaves 5Hz-600kHz in 5 bandsOUTPUT LEVELWithii ± 1db band to bandDISTORTION:Less than 1% from 5kHz to 600kHzCALIBRATION ACCURACY:

2% from 50Hz to 600kHz 2:.1Hz from5Hz to 50HzDIAL:6in. with 12-1 gear drive ratio provides a

scale length of 7ft over the 5 bandsOUTPUT LEVEL:Sinewave 10v RMS into 600 2Squarewave 10v P -P, 4 position step atten-uator and continuous amplitude controlSQUAREWAVE RISE TIME:0.2o.ecSIZE:111/2 x 9 x 111/4.WEIGHT:24 lb

$199.95

SUPPLY VOLTAGE:117vac 50/60Hz standard 220vac 50-60vac50-60Hz available

AUGUST 1967 53

DISCRIMINATORTRANSFORMER T203r

I.

4.Vze

8

Fig. 2-The last pair of transistors in the IFsection of the integrated circuit function inthe same manner as the first pair of transistors.

III The previous article in this seriesexplained how a temperature -com-pensated, voltage -regulating transis-tor (Q9) is used in integrated circuit,IC201, to provide a nearly constantsupply voltage to the first five am-plifier stages. These stages containstill another circuit to improve theirstability further.

A Negative Feedback CircuitA resistor (R15) couples the base

of transistor Q2 to the emitter oftransistor Q6 (Fig. 1). Since theportion of the integrated circuitshown in this figure is used toamplify FM IF signals, the circuithandles frequencies of around4.5MHz. The 0.1,0 capacitor con-nected to the base of transistor Q2is, therefore, able to short these acsignals to ground. The ac portion ofthe transistor (Q6) emitter currentdevelops an ac voltage across resis-tors R7 and R15, while virtuallynone of this ac voltage appears atthe base of transistor Q2. If thevalue of resistor R15 is sufficientlylarge, it does not significantly re-duce the ac voltage across resistorR7.

If a temperature change or slightproduction variance results in anincreased dc current, a larger dcvoltage drop will result acrossresistor R7. This increases the for-ward bias of transistor Q2, increas-ing its collector current and thecurrent flow through resistor R2.

With a greater voltage drop acrossthat resistor, the base of transistorQ3 becomes less positive and areduction occurs in its dc collector

The Thirteenth Article in a Continuing Series

Understand integrated circuits and most solid-stateelectronic circuits will be easier to service

Semiconductorscurrent. This, in turn, results inreduced current through transistorQ4, increased current throughtransistor 05 and a reduced dc cur-rent through transistor Q6. The dcvoltage drop across resistor R7 is,

therefore, reduced and negativefeedback has taken place.

Transistors Q7 and Q8 function(Fig. 2) in the same manner astransistors Q1 and Q2 (describedwith Fig. 5 in the July 1967 article).A positive pulse applied to the baseof transistor Q7 causes that transis-tor to conduct more current andtransistor Q8 to conduct less cur-rent. This results in a reducedvoltage drop across the primarywinding of transformer T203, and

Fig. 3-A second vokage-regulating transistor(Q10) is also used to bias a portion of theintegrated circuit.

INPUTTRANSFORMER

T 201

4.5 MHzINPUT I

-s-

01

R14

05

the winding becomes more positive.This differential amplifier circuit

(Fig. 2) need not be balanced andthe increased current through tran-sistor Q7 may not necessarily equalthe decreased current through tran-sistor Q8. A 0.014 capacitorshunts any of the resulting 4.5MHzsignal, which may otherwise be de-veloped across the voltage source(Vcc), to ground.

Transistor Q10 (Fig. 3) functionsin the same manner as transistorQ9 (described with Fig. 13 of theJuly 1967 article). Just as theequivalent to the circuit containingtransistor Q9 (Fig. 4 of the pre-vious article) is shown as Fig. 14

in that article, the equivalent to the

Vcc

08

DISCRIMINATORTRANSFORMER T203r-.

11 13 E-ft-r1-I .

/ IN01

010

D2

RIO D4= D3

R12 SRII

C3

CI

54ELECTRONIC TECHNICIAN

from A to Icircuit containing transistor Q10(Fig. 3) is shown in Fig. 4. Transis-tor Q10 supplies a temperature -compensated, virtually constantvoltage source to the base of transis-tor Q5, the base of transistor Q8, asecondary winding of transformerT203 and resistor R14, which isconnected to a secondary windingof transformer T201.

When no signal is induced intothe secondary winding of trans-former T201, the base of transistorQ1 has a 2.1v bias - there havingbeen an insignificant dc voltagedrop across the transformer's sec-ondary winding and resistor R14.The 4.5MHz signal induced in thetransformer's secondary winding

Fig. 4-The equivalent of a voltage -regulatingtransistor is substituted for transistor Q10.

INPUTTRANSFORMER

T 201

4.5 MHz IINPUT

01

R14

05

01

R2 03

04

RIO

5 06

R4

05

R15

increases and decreases the transis-tor's base bias at that frequency.

Specifications indicate that the4.5MHz signal applied to terminal1 of the integrated circuit (Fig. 4of the July 1967 article) experiencesa gain of about 60db with a band-width of 70 to 801(11z before itleaves the circuit at terminal 5.

The frequency of the FM IFsignal, amplified in the first portionof the integrated circuit, varies withthe audio signal it contains. Thisvarying IF signal is applied to theprimary winding of discriminatortransformer T203 (Fig. 3).

The Discriminator TransformerWhen a transformer has a single

VCC

DISCRIMINATORTRANSFORMER T203

E-c$-:- I

T_

4.

vs

Re

D431E 31ED3

=C2

,R12 Ri I

Yes

Fig. 1-Negative feedback improves the decurrent stability of the first area of the int*.grated circuit.

secondary winding, the voltages inthe two leads at the ends of thewinding (Fig. 5) are 180deg out ofphase - when one lead is positive,the other is negative. If anothersecondary winding is connected tothe first secondary winding (Fig. 6),the voltages in the two leads con-nected to the first secondary wind-ing are still 180deg out of phase.The voltage induced in the thirdlead, however, need not have a fixedphase relationship with the othervoltages. The phase of the voltage atthe third lead depends on how thesecond coil is wound and the fre-quency of the signal induced.

Some less experienced tech-nicians may not be familiar with the

F:Fig. 5-The voltages present atthe transformer's two secondaryleads are 'Indus out of phase.

=C3-CI

0

F2

1D1

Fig. 6-The voltages present at two of thetransformer's secondary leads remain 180degout of phase, while the phase relationship ofthe vo'tages present at the third lead varieswith the signal's frequency.

AUGUST 1967 55

Semiconductors ...term "phase angle." This term isused either to indicate portions of asinewave or to indicate the degree oftime lag between two sinewaves ofthe same frequency.

Positive and negative changes ofvoltage generally appear on thescreen of an oscilloscope as a sine -wave - whether the signal observedis from an ac power line or someunmodulated RF source.

When a line is horizontal (zerodeg), it has no height (Fig. 7), andthe corresponding portion of thesinewave (Fig. 8) is at zero voltage.After rotating 45deg, the line hasrisen slightly more than 70 percentof its full height, and the correspond-ing portion of the sinewave isslightly more than 70 percent of itsmaximum positive voltage. Afterrotating 90deg, the line is at its fullheight, and the corresponding por-tion of the sinewave is at its peakpositive voltage. At 135deg, the lineis again only slightly more than 70percent of its full height, and thecorresponding portion of the sine -wave is slightly more than 70 per -

Fig. 7-The height of a rotating line corre-sponds to the voltages that form a sinewave.

-Y

0

-r

cent of its maximum positive voltage.At 180deg, the line is again hori-zontal, and the corresponding por-tion of the sinewave is at a zerovoltage. By the time the line hasrotated 225deg, it has dropped toslightly more than 70 percent of itslength below the horizontal, and thecorresponding portion of the sine -wave is slightly more than 70 per-cent of its maximum negativevoltage. By the time the line hasrotated 270deg, it has dropped itsfull length below the horizontal,and the corresponding portion of thesinewave is at its peak negativevoltage. After rotating 315deg, theline is again slightly more than 70percent of its full length below thehorizontal, and the voltage at thecorresponding portion of the sine -wave has been reduced to about 70percent of the maximum negativevoltage. When the line has rotated360deg and has returned to itsinitial horizontal position (zero deg),it again has no height, and thecorresponding portion of the sine -wave has returned to zero volts.

+Y

0 0in 0it a) 2

-Y

4-7.1vVIA R240

Fig. 8-A sinewave canbe divided into variousphase angles.

180°

0 0 0 by two capacitors.1/4..4

" - 60°" " rf) o3r 0°

The number of times the linerotates each second corresponds tothe frequency of the sinewave. Iftwo lines are rotating at the samefrequency, the angle between thetwo rotating lines corresponds tothe angle between their two corres-ponding sinewaves.

The Discriminator Circuit

The ac signal in the third lead inthe secondary of the discriminatortransformer (Fig. 9) is shorted toground by a 0.1,2f and a 0.014 ca-pacitor. The discriminator trans-former is designed in such a mannerthat at 4.5MHz the voltages inducedacross the grounded extra secondarylead are 90deg out of phase withthe voltages induced across theother two secondary leads.

For convenience, the first sec-ondary of discriminator transformerT203 is shown in Fig. 13 of thisarticle as coils 1 and 2 while thesecond secondary is shown as coil3. Curve A (Fig. 10) represents thevoltages induced across coil 2 at4.5MHz while curve B represents

DISCRIMINATORTRANSFORMER T 203I-

Fig. 9-The IF signal de-veloped at the discrim-inator transformer's thirdlead is shorted to ground

C2 -

D3

C3

CI


the voltages induced across coil 3at the same frequency. Note that thetwo curves are shown 90deg out ofphase. For convenience, we will as-sume that the amplitude of the twocurves is the same. The voltage ap-plied to the anode of diode D4 isequal to the sum of the voltages de-veloped across coils 2 and 3. CurveC represents the sum of the twocurves (curve C = curve A +curve B).

Curve D represents the voltagesdeveloped across coil 1, while curveE, like curve B (curve E = curveB), represents the voltages de-veloped across coil 3. The voltagesapplied to the cathode of diode D3is shown as curve F and is the sumof the voltages developed acrosscoils 1 and 3 (curve F = curve D+ curve E).

Curves C and F are of equal am-plitude, and the same amount ofvoltage is applied to both diodes.

From curves A and D (Fig. 10)we see that the voltages developedacross coils 1 and 2 of the firstsecondary are 180deg out of phase

Flu LIEV

101'

with each other, as in Fig. 6. Thevoltages applied to diodes D4 andD3, however, as can be seen fromcurves C and F, are not 180deg outof phase. They are instead 90degout of phase (0 = 90deg). Thevoltages developed across coil 3have resulted in a phase shift in thevoltages applied to the two diodes.

The curves in Fig. 11 show thevoltages developed across the samecoils (1, 2 and 3) at a frequencybelow 4.5MHz. At this lower fre-quency, the voltages developedacross coil 3 (curves B and E) arenot 90deg out of phase with thevoltages developed across coils 1

and 2. They are instead 18deg outof phase with the voltages developedacross coil 2 (curve A) and 162degout of phase with the voltages de-veloped across coil 1 (curve D). Thevoltage applied to diode D4 at thislower frequency is shown by curveC in Fig. 11 (curve C = curve A+ curve B). Curve C, as you mayknow, was formed by adding theamplitudes of curves A and B ateach point along their horizontal

axis and plotting the total amplitudealong corresponding points on an-other horizontal axis. The amplitudeof curve C is greater at the lowerfrequency (Fig. 11) than it was at4.5MHz (Fig. 10) - although theamplitude of curves A and B havebeen the same at both frequencies.The change in amplitude of curveC has resulted merely from a changein the phase angle between curvesA and B.

The voltages applied to diode D3at this lower frequency are shownby curve F in Fig. 11. The changein the phase angle of the voltagesinduced in coil 3 has reduced thevoltages represented by this curve(F).

The voltages applied to diode D4(represented by curve C) are 90degout of phase (0 = 90deg) with thevoltages applied to diode D3 (rep-resented by curve F).

When the frequency of the IFsignal is greater than 4.5MHz, thevoltages induced across coil 3 havestill another phase relationship withthe voltages induced across coils 1

Fig. 10-Voltages induced in various por- Fig. 11-Voltages induced in various portions Fig. 12-Voltages induced in various portionstions of the discriminator transformer at of the discriminator transformer at a fre- of the discriminator transformer at a frr4.5MHz. quency below 4.5MHz. quency above 4.5MHz.

AUGUST 1967 57

Semiconductors ...and 2 (Fig. 12). In this third ex-ample, the voltages induced acrosscoil 3 (curve B) are 45deg out ofphase with the voltages inducedacross coil 2 (curve A) and 135degout of phase with the voltages in-duced across coil 1 (curve D). As aresult of this phase shift, larger volt-ages are applied to diode D3 thanto diode D4 (amplitude of curve E> amplitude of curve C).

Again, the voltages applied todiode D4 are 90deg out of phase(0 = 90 deg) with the voltages ap-plied to diode D3. This phase re-lationship is the same as those thatoccurred at 4.5MHz and the otherlower frequency. The phase relation-ship of the voltages applied to thetwo diodes (0) will not change withthe frequency of the IF signal -unless the frequency is one at whichthe phase of the voltages inducedacross coil 3 is the same as thephase of those induced across coil1 or 2. The frequency shift normallyexperienced, however, is not great

enough to produce such a phaseshift in the discriminator coils usedin this circuit. The phase angle (0)between the voltages applied to thetwo diodes is instead dependent onthe relationship of the voltages in-duced across coil 3 to the voltagesinduced across coils 1 and 2. CurvesC and F are 90deg out of phase(0 = 90deg) only when the am-plitudes of curves B and E are thesame height as curves A and D.(Curve B curve E, and the am-plitude of curve A = amplitude ofcurve D. 0 = 90deg when amplitudeof curve B = amplitude of curveA = amplitude of curve D.) In thenext article of this series we will seethat, with the capacitors in thedetector circuit (Fig. 13), we neednot be concerned with the phaseangles of the voltages applied tothe diodes (D4 and D3).

Curves C and F, shown in Fig.13, represent the voltages appliedto the two diodes (D4 and D5) at4.5MHz (these curves are respec-

=C5

®..--C2

C4

04 D3

RI2 RII

tively the same as curves C and Fin Fig. 10). On page 61 in theAugust 1966 article of this series,we observed that electrical currentsflow from negative to positive.These currents can pass only fromthe anode to the cathode of a diode.Diode D4 in Fig. 13 will conductcurrent only when postive voltagesare applied to its anode (as shownin Fig. 3A on page 61 of the August1966 article), and diode D3 willconduct current only when negativevoltages are applied to its cathode(as shown in Fig. 3B of the samearticle).

Diode D4 (Fig. 13) is connectedin series with resistor R12, anddiode D3 is connected in series withresistor R11. When capacitors Cland C2 are not connected in thecircuit, the current flowing throughthe diodes will also flow throughthe series resistors. Under theseconditions, the resulting voltagedrops across resistors R12 and R11resemble curves G and I. Only posi-tive half -cycles appear across re-sistor R12, while only negative half -cycles appear across resistor R11.The resulting waveforms are thesame as those shown in Fig. 3 ofthe August 1966 article.

The next article in this series willdescribe capacitor time constantsand their effect on the waveformsin the discriminator circuit. Thecascade amplifier, representing theundiscussed portion of the integratedcircuit, IC201, will also be de -

0 scribed in detail.

-C3 ®

CI

rb

Fig. 13-Voltages pin an unbiased discriminator

circuit at 4.5MHZ.


THE APPRENTICE AND THE PRO

A technician makeshis first house call

and learns how thepros operate

Part two of a continuing series

On a Monday morning, in theearly spring of 1962, Don Jackson,the TV -radio apprentice, was onthe way to his first home -call, andhis teacher, Bob Morkin, a certifiedtechnician and "pro," wasted notime initiating Don to some of thesimple customer -relations principlesinvolved in making house calls. Forone thing, he was told to take offhis rubber overshoes at the frontdoor, leave them on the front porchand wipe his shoes on the doormat.

"And remember one very impor-tant thing, I'll do all the talkingwhile we're in the house," Bobsmiled. "Also, since we have a fewminutes before we arrive at our firstcall, now's a good time to beginlearning some of the importantpolices of our operation.

Learning the Ropes

"For example," Bob continued,"there have been arguments in theindustry for years about 'home re-pairs' versus 'shop repairs.' And ourcompany does not make major re-pairs in the home. We don't replaceresistors, capacitors or other com-ponents, except tubes, unless the setis in warranty. In this case we doinstall a few flybacks, yokes andcertain resistors and capacitors-when the defective parts can beiso'ated easily and installed quickly.But on older sets, when more thana tube is necessary, we take thechassis to the shop. No techniciancan do a good job repairing sets inthe home. You can't wait around inthe house while the set 'cooks' forhours." Don was thoughtful as he

EIA Launches Training Program

Washington, May 16, 1967-TFe service committee of theElectronic Industries Assoc. (EIA) launches a long-term programin the areas of recruiting, training and upgrading electronicstechnicians needed in ever increasing numbers by electronicsservice -dealers.

This program is the latest phase in the association's long-standing effort to provide adequate service support for thecomplex electronic products used today and planned for thefuture.

Operating under instructions from EIA's consumer productsdivision executive committee, the service committee outlined aseries of actions to be taken in the following areas:

1. Career guidance through brochures, films, exhibits,lectures and every other form of communications to makepotential service personnel, and the people who counsel themin the schools, aware of the ca-eer opportunities awaitingthem in the consumer -products service area of the electronicsfield.

2. Vocational education upgrading to bring electronicsvocational education in this country up to the sophisticatedlevel demanded by the revolutionary technology now trans-forming consumer electronics-via teacher institutes, corres-pondence courses, bulletins, scholarships, etc.

3. Coordination with the service activities of manu-facturers, distributors, dealers aid other interested industrygroups.

The service technician develooment program's basic teamwill soon be expanded by the addition of an EIA staff specialistin technical vocational education.

AUGUST 1967 59

began to realize how much there wasto learn about this business.

"Another thing," Bob said, as hepushed on with the briefing, "theboss is a stickler for methodicalprocedures. You'll soon begin tolearn how to work without wastedmotions. And you'll learn that cer-tain movements are made beforeothers. But, after a while, you'lldo it fast and automatically withoutthinking about it.

"For instance, when we arrive atthe front door on this call, and afteryou've removed your overshoes andwiped your shoes, take the smalldrop -cloth from the caddy and carryit inside-rolled up. When youarrive in the room where the setis located, place the drop -cloth onthe floor-whether there's a rug onthe floor or not-and place it to

the right or left rear side of the setabout a foot from the wall. I'll putthe caddy on that drop -cloth asecond later. If you were alone,you'd carry the caddy in one handand the small drop -cloth in the otherand you'd spread the cloth on thefloor with one hand and then setthe caddy on it.

"Then," Bob continued, "whileI switch the set on and take a look,open the caddy and take out thelarge drop -cloth and place it on topof the open caddy. Depending on theparticular situation, you'll probablyhelp me move the set away fromthe wall-and we'll turn it at anangle to the right or left-dependingagain on where the set is locatedand its relationship to the caddy.

"After this, spread the big drop -cloth on the floor back of the set,

get a IA in. hex -head wrench, aPhillips screwdriver and a cheatercord from the caddy and place themside by side on the top -right cornerof the drop -cloth. Then you standnear me on my left or right, depend-ing on which way the set is turned.You'll see what I mean after we getthe set away from the wall. What-ever else I ask for after that, re-move it from the caddy and handit to me. Thereafter, watch everymove I make-and keep your eyesand ears open."

Don was going over every stepof the routine in his mind as Bobhad outlined it.

"Can you remember all that?"Bob's voice interrupted Don'sthoughts.

"I've memorized every step of it,I think," Don said, grinning withconfidence.

"OK. Here we are now," Bobsaid, as he pulled the service truckalongside the curb and parked infront of the house.

Audio but No Picture

Everything went smoothly, ac-cording to plan, and Bob had alreadyswitched the TV set on. The screenof the 21in. B/W console lit up witha bright raster but no pictureshowed. Bob switched the tuner toall local channels and the screen wasthe same. The audio seemed strongon all channels as Bob turned up thevolume briefly and then backed it offagain. Then he switched the set offand glanced at the service ordercard. Following TROUBLE SYMPTOMSprinted on the card, he read: "goodaudio but no picture."

He stepped to one side of theset, removed the power cord fromthe wall outlet and then the twomen, facing slightly forward, liftedthe set, moved it forward slightlyand turned it about 45deg to theleft. The right rear leg (viewedfrom the back) was about 18in.from the wall.

Don picked up the large drop -cloth from the caddy, spread it on


the floor back of the set and placedthe tools and cheater cord on theright top corner of the drop -cloth.He then stepped to the left.

Now Bob moved quickly behindthe set, picked up the hex -headwrench and Don noted that the firstscrew he removed from the set'sback cover was just below the acinterlock. Bob then picked up thePhillips -head screwdriver and re-moved one of the eight screws hav-ing captive washers that held theback to the cabinet-the screw inthe top left corner. Don also notedthat Bob continued to remove thescrews in a counter -clockwise direc-tion until the seventh screw, topright, was removed. Then Bob's lefthand suddenly grasped the "bump"on the back which covered the CRTsocket. He then removed the eighthand last screw, the one at the topcenter of the set's back. Suddenlyagain, Bob's right hand relieved hisleft hand which went quickly to theinterlock, pulled on it lightly andthe back came off. Bob then placedthe back against the wall out of theway to the right. Don had noticedby his wristwatch that Bob had re-moved the TV's back in less thanone minute.

Bob then turned to Don andwhispered, "did you notice howthe back was removed?"

"Sure did," Don said."Remember the procedure and do

it the same way every time. Thescrew at the top is removed lastto prevent the back from turningto one side or dropping down andcracking up something on the CRTneck. Of course, you don't have toworry too much about this on mostmodern wide-angle, short -neckedCRTs-but you have to watch iton some old sets," Bob said. "Be-sides, if you remove the screws ina regular way each time, you'll doit faster after awhile."

"Now we'll see if we can fix thisset. We think the video output tubeis defective. This set uses ih of a12AU7 as video output. Give mea 12AU7, please," Bob said.

When the defective tube was re-placed, the picture came in good.

"The mirror," Bob said.Bob removed a pencil from his

shirt pocket and began to tap lightlyon one tube after another, watchingthe screen in the mirror. The screenflashed two or three times and Bobsaid, "6AX4 please." Don removedone from the caddy and handed itto him.

Bob then showed Don how toremove the front safety glass. Hethen cleaned the CRT face and theglass. Bob adjusted the verticalheight and linearity controls slightly.

Finally, Bob said, "I think that'sit. Now I want you to replace theback on the set," and he removedthe cheater cord, rolled it up neatly,picked up the mirror and placedboth in the caddy.

Don experienced some slightdifficulty with the interlock for amoment but quickly replaced theinterlock screw, thescrew, then continued replacing theother screws. When he had finishedhe picked up the tools, rolled up thelarge drop -cloth and placed every-thing in the caddy. The two men thenmoved the set back to its normalposition near the wall.

Bob Morkin explained to the lady -of -the -house what had been doneto the set. Since this was a new,first-time customer, he went intodetails, explaining about the replacedtubes, cleaning the screen and theadjustments. He explained about theservice charge.

"The $5.95 charge for service,"he said, "is our cost of providingyou with honest and efficient service.It includes a portion of the rent andelectricity at the store. It includes aportion of my salary, cost of oper-ating the service truck, cost of toolsand many other necessary oper-ating expenses. Our company makeslittle or no profit on service callsat the price we charge . . ."

The lady interrupted Bob andasked, "What if one of the tubesyou replaced burns out?"

"If that happens within a 90 -day

period you get another tube free,"Bob answered. "But don't misunder-stand me," he added quickly. "Thetube. is free because the manufac-turer gives us another if it failswithin the 90 -day period. But themanufacturer won't pay us for put-ting the tube in your set. The cost ofservice remains the same. Thecharge will be the same as it wastoday."

The lady's brow puckered slightly,but she smiled and said, "Thatseems logical and fair, but why doyou need two technicians on a serv-ice call?"

"Here it comes," Don thought,"now Bob is stuck!" But Don under-rated Bob's human -relations andbusiness know-how.

"We don't need two men," Bobsaid quickly. "Don here," he said,turning to me, "has studied TV serv-icing for more than a year in tech-nical school but he is an apprentice

in training. He's likean intern-a doctor in training at ahospital. It will be three or fouryears before he'll be allowed to makea service call alone and be entrustedwith the responsibility of repairingyour TV or Hi FL Our companypays him a salary for doing otherwork around the shop-but noneof his salary comes from service -call charges."

Bob gave the set owner the twoold tubes explaining that one ofthem, the 6AX4, would probablytest OK on a "drug -store" tubetester but it had a defect and was re-placed before it broke down andcaused another service charge. Healso explained that a TV set-anyTV set-could break down withoutwarning at any time.

The two men left the house andentered the service truck. Bob Mor-kin called the shop on the two-wayradio and recorded two calls for theafternoon. Then the truck took offeastward across town to the nextservice call on the list. Bob and Donhad been in the house a full halfhour. Alone, the call would havetaken Bob only about 20 minutes.

AUGUST 1967 61

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80

. . . The Easy Way

continued from page 48

amount of positive delayed AGC

voltage fed to the tuner and this is

controlled by the 2nd IF collector

current. Bending of vertical lines

usually indicates an overload condi-

tion. Check the AGC control for

proper adjustment and then check

AGC circuit voltages - following

manufacturers'service notes. Pay

special attention to sync and keying

pulses from the flyback. Scope

checks here will speed your work in

locating faults.The vertical output stages on

some solid-state TVs have a bias

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Allied Radio Corp.

Amperex Electronic Corp.

35.36

3rd Cover

Arco Electronics29

Armco Steel Corp.69

B&K Div., Dynascan Corp.25

Castle TV Tuner Service .76

Channel Master Corp.30-31

Chemtronics, Inc.80

Cleveland Institute of Electronics . 73, 79

Electro-Voice, Inc.77

ELECTRONIC TECHNICIANBook Club ..62-65

Finney Co.26.27

GC Electronics Co.22

International Crystal Mfg. Co. . 28

Jensen Mfg. Div., The Muter Co. 24

Jerrold Electronics Corp. 2nd Cover

JFD Electronics Co.67

Matsushita Electric71

Microflame, Inc.71

Miller Co., J. W.77

Mosley Electronics72

Precision Apparatus Div., Dynascan Corp... 19

Quietrole Co.78

Radio Corp. of America

RCA Electronic Components

& Devices4th Cover

RCA Sales Corp.27

S & A Electronics, Inc.34

Sencore, Inc.33, 74, 79

Sprague Products Co.23

Triplett Electrical Instrument Co. 70

Weller Electric Corp.78

Yeats Appliance Dolly Sales Co. 71

Zenith Sales Corp.76

control that must be set in conjunc-

tion with the height and linearity

controls. Checkmanufacturers' serv-

ice manuals when adjusting these

controls. In this set, the vertical

oscillator will lock at 30Hz instead

of 60Hz if Y201 fails. This will

place the vertical blanking bar in

the center of the screen and also

cause the vertical hold to be very

soft.Procedures for troubleshooting

the audio section of this set are the

same as for an FM transistor radio.

Signal injection works wonders.

Many TV manufacturers supply a

circuit template for rapid location of

components and test points (see Fig.

11). This, along with "roadmap-

Fig. 11-Circuit template is used to locate

components and test points quickly.

ping" which appears on the circuit

board, can speed your checking

processes.When the problem is narrowed

down to a specific section of a set,

use an in-circuit transistor tester.

You can locate defective transistors

very quickly in this way. Although

we have been told to suspect transis-

tors last, our experience shows that

they should be checked first. We

find many shorted transistors - fowhatever cause. And when a transistor shorts, it almost always burn

up the emitter resistor.One other thing to remember:

this set is operated on a 12v autpower supply, high spike pulse

from the car altenator will fr

quently destroy the horizontal of

put transistor.Don't fear these "little monster.

Know your solid-state circuits thfoughly, know the precautions ymust take when troubleshooting 2

repairing them. You can then dboldly into their "innards" and scbecome known as the solid-si

specialist in your area.

ELECTRONIC TECHNIC

One out of every fiveprofessional servicemen

has switched to AmperexTV replacement tubes

It takes a lot of quality to change the buying habitsof 200%o of the most knowledgeable technicians inthe business. These servicemen are following thepattern set by the leading TV manufacturers, who aredesigning more and more of their quality lines aroundtubes originated by Amperex. The Amperex line ofpopular types is expanding all the time. Look for thegreen and yellow cartons at your distributor's or write:Amperex Electronic Corp., Hicksville, L. I N.Y. 11802.

AmperexTOMORROW'S THINKING IN TODAY'S PRODUCTS


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RCA'S NEW FIELD SERVICE GUIDE, ERT-200 helps youmake all adjustments on all RCA color sets from 1955to 1966 that can be performed in the home ... includingstep-by-step procedure for replacing a color picture tube.

WHAT THIS GUIDE CONTAINS: Schematics on all RCA color sets from 1955 to 1966 Field service adjustments (AGC, linearity, centering, etc. Convergence, purity and black and white setup

adjustments Parts lists Wave forms keyed to test points for majority of chassis Top and rear chassis views Photos of typical receivers Index of models from CTC2 through CTC20 Separate section on tuner schematics Separate section on remote tuner schematics

Amme. -3motomor

See your RCA Tube Distributor today and arrange to get your copy.

RCA Electronic Components and Devices. Harrison, N.J. 07029

Three part index lets you look up the set you are working onby model number, name or chassis number. You'll find theERT-200 Field Service Guide indispensable. There's noth-ing like it on house calls for RCA color sets.

FIELD -SERVICE GUIDERCA COLOR TV RECEIVERS

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The Most Trusted Name in Electronics

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Documents

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