GE Photofact Folder 21C115 Installation instructions

PHOTO FACT* Fold er
GENERALELECTRIC
MODELS 21C115, 21T14 (Ch. 21TF)
VOLUME
CONTROL
ON-OFF SW
FINE
TUNING
CONTRAST
CONTROL
VERT. HOLD
CONTROLBRIGHTNESS
CONTROL
CHANNEL
SELECTOR
GENERAL ELECTRIC MODEL 21X14
TRADE NAME GeneralElectric Models 21C115, 21T14(Ch. 21TF)
MANUFACTURER GeneralElectric Co., Electronics Dept., ElectronicsPark,Syracuse, N.Y.
TYPE SET Television Receiver
TUBES Twenty-one
POWERSUPPLY 110-120Volts AC-60 cycle RATING 1.92 Amp. (a)117 Volts AC
TUNINGRANGE— Channels 2 thru 13, Video IF45. 75MC, Sound IF45. 75MC, Sound IF41. 25MC (Intercarrier)
INDEX
Alignment Instructions 6,7 Photographs (Cont)
DisassemblyInstructions ..,.-. 18 Trans., Inductor & Alignment Identification .............. 17
Horizontal Sweep Circuit Adjustments 11 ResistanceMeasurements 8
Parts List and Descriptions 14, 15, 16 Servicing inthe Field 18
PhotographsSchematic 2
Cabinet-Rear View 11 Terminal LocationChart 13
Capacitor Identification 4,9 Trouble Shooting Aids , 12,17
Chassis-Top View 3 Tube Failure Check Chart ...... . , ,. 3
RF Tuner 10 Tube PlacementChart (Bottom View) 8
Resistor Identification 19,20 TubePlacementChart(Top View) 5
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HOWARD W. SAMS & CO.,INC. • Indianapolis 5, Indiana
"Thelisting ofany available replacementpartherein does not constitute inany
case a recommendation,warranty or guaranty by Howard W. Sams & Co., Inc.,
as tothe quality and suitability of such replacement part. The numbers of these
partshavebeen compiled frominformationfurnished to Howard W. Sams & Co.,
Inc., bythe manufacturers ofthe particulartype of replacement part listed."
"Reproduction or use,without express permission, of editorial or pictorial con-
tent, inany manner, is prohibited. No patent liability is assumedwithrespect to
the useofthe informationcontained herein. Copyright1954 by Howard W.
Sams & Co.,Inc., Indianapolis 5, Indiana, U.S.of America. Copyright under In-
ternational CopyrightUnion. All rights reserved underInter-AmericanCopyright
Union 11910) by Howard W. Sams & Co., fnc." Printed inU.S.of America
DATE 2-54
SET 229 FOLDER 7

RE AMP
©6BC5
»W -f
DOTTED IN WWTS ARC NOT USED INALL
MODELS. WVCN DOTTED IN FARTS ARE
USED POINTS MARKED X ARE BROKEN.
WAVE FORMS TAKEN WITH CONTROLS
StTTO PRODUCE 30 VOLT3 PEAK 1O
PEAK SIGNAL. AT PICTURE TUBE
A PHOTOFACT STANDARD NOTATION SCHEMATIC
©Howord W. Soms & Co.,Inc. 1954
PAGE 2

GENERAL ELECTRIC
MODELS 21C115, 21T14 (Ch. 21TF)

For tube location see
Tube Placementchartpage 5.
CHASSIS TOP VIEW
SET229 FOLDER 7
PAGE 3

CHASSIS BOTTOM VIEW-CAPACI
PAGE 4

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:APACITORIDENTIFICATION
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PAGE 9

TUBE PLACEMENT CHART
RATIO DEIIFAMP
US LI7LI6
®® ® (in.
VERTOUTPUT
TOP VIEW
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jo 5
933
K>
TUBE FAILURE CHECK CHART
The following chart lists tubeswhosefailures are most likely to produce the indicatedsymptoms.
Refer to tubeplacement chart for location and type of tube.
POWERSUPPLY FAILURE
No raster, no sound - V19, V20, Fuse (Ml)
LOSS OF PICTURE OR SOUND
No pic, no sound, has raster - V2,V3,V4,V5
No pic, no sound, has snow - VI, V2,V3
No pic, has sound, has raster - V6,V21
Has pic, no sound - V7,V8,V9, V10
Overloaded picture -
SYNC FAILURE
No vert, sync - V12, V13, V14
No horiz. sync - V12, V15
No vert, or horiz. sync - V12
SWEEPFAILURE
No raster, has sound - V15, V16,V17, V18, V21
No vertical deflection - V13, V14
Poor vert, linearity or foldover -V13, V14
Poor horiz. linearity or foldover - V15, V16, V17
Narrowpicture - V15, V16, V17, V18, V19, V20
Vert, off freq. - V12, V13, V14
Horiz. off freq. - V12, V15
10
SET 229 FOLDER 7
PAGE 5

ALIGNMENT INSTRUCTIONS
1.
2.
3.
4.
5.
6.
7.
6.
7.
ALIGNMENT INSTRUCTIONS-READ CAREFULLY BEFORE ATTEMPTINGALIGNMENT
The high voltageshock hazard maybe eliminated by removing the horizontal multivibratortube from its socket.
Allow 20 minute warm-upperiod for receiver and test equipment.
TRAP ALIGNMENT
Turn the fine tuning control andthe contrast control fully clockwise. Turn the volume control andthe area control fully counter clockwise.
DUMMY
ANTENNA
Direct
SWEEP
GENERATOR
COUPLING
High side to point <&> .
Low side to chassis.
"
High side to point <Q> .
Low side to chassis.
SWEEP
GENERATOR
FREQUENCY
Not used
MARKER
GENERATOR
FREQUENCY
47.25MC
(400-UMod)
41.25MC
4. SMC
(400%Mod)
CHANNEL
11
"
CONNECT
SCOPE
Vert. Amp. to point
^^ . Low side to
chassis.
"
Vert. Amp.thru de-
tector (Fig.l) to point
^^ . Low side to
chassis.
ADJUST
Al
A2
A3
REMARKS
Remove VllandV16 from their sockets.
Adjust for MINIMUM 400% indication on
scope. If necessary, set scope gain to
maximum.
Adjust for MINIMUM 4001 indication on
scope.
VIDEO IF ALIGNMENT
Connect the negativelead ofa 4.5 volt bias supply to pointo^ . Connect positive lead to chassis.
Turn contrast control fully counterclockwise.
Remove the converter tube from its socket and replace with 6J6 which haspin1 removed.Thiswilldisable the local oscillator and reduce the
possibility of erroneousindications.
Connect the synchronizedsweepvoltage from the sweepgenerator tothe horizontal input ofthe oscilloscope for horizontaldeflection.
DUMMY
ANTENNA
Direct
SWEEP
GENERATOR
COUPLING
High side toanun-
grounded tube shield
floating over dummy
converter tube. Low
side to chassis.
SWEEP
GENERATOR
FREQUENCY
44MC
(10MC Swp)
MARKER
GENERATOR
FREQUENCY
44.15MC
44.15MC
44.15MC
45.25MC
42.9MC
41.25MC
42. SMC
45.0MC
45.75MC
47.25MC
CHANNE1
11
CONNECT
SCOPE
Vert. Amp.thru
10KT2 resistor to point
<.iS . Low side to
chassis.
ADJUST
A4,
AS
A6
A7
A8
REMARKS
Calibrate scope so that .75 volt produces
2 inch vertical deflection. Peak A4 thru
A8 for maxitnumum response at marker
frequency.
Adjust A4 thru A8for response similar
to Fig. 2. If necessary, retouch A4, AS
and A6to shape peakregion of curve.
SOUND IF ALIGNMENT USING AM SIGNAL GENERATOR AND VTVM
Connect two matched 100KB (±1%) resistors in series from polnt<f\to chassis. The junction of these two resistors is alignment polnt<&>as
shown onthe schematic. v^ ^^
DUMMY
ANTENNA
.01MFD
SIGNAL
GENERATOR
COUPLING
High side topin1 (grid)
of 6CB6 (V7) . Low side
to chassis .
"
SIGNAL
GENERATOR
FREQUENCY
4. SMC
(Unmod)
"
CHANNEL
Any non-
interfer-
ing
channel
"
CONNECTADJUST
VTVM ADJUST
DC probe to point<y> . A9, A10,
Common to chassis. All
DC probe to point &> A12
Common to point &) •
REMARKS
Adjust for maximumdeflection.
Adjust for zero reading. A positive and negative read-
ing will be obtained on either side ofthe correct
setting.
SOUND IF A1IGNMENTUSING FM SIGNALGENERATOR AND OSCILLOSCOPE
Use frequencymodulated signal with 60^ modulated and 450KC sweep. Use 120^ sawtooth voltage in scope for horizontal deflection.
DUMMY
ANTENNA
. 01MFD
SWEEP
GENERATOR
COUPLING
High side to pin 1 (grid)
of 6CB6 (V7) . Low side
to chassis.
SWEEP
GENERATOR
FREQUENCY
4. SMC
(450KC Swp)
MARKER
GENERATOR
FREQUENCY
4. SMC
CHANNEL
Any non-
interfer-
ing
channel
CONNECT
SCOPE
Vert. Amp.thru
10K« to point OA .
Low side to chassis.
Vert. Amp.thru
10KJJ to point qb .
Low side to chassis.
ADJUST
A9.A10
All
A12
REMARKS
Disconnect stabilizer capacitor C4. Adjust
for curve of maximumamplitude and
symmetry asin Fig. 3.
Reconnect stabilizer capacitor C4. Adjust
so that 4. SMC occurs at center of cross-
over lines asin Fig. 4. SLIGHTLYretouch
Allfor maximumamplitude and stralghtness
of crossover lines .
SOUND IF ALIGNMENT USING TV SIGNAL AND VTVM
Replace Vll and V16.
Remove dummy oscillator tube and replaceoriginal 6J6 inits socket
Turn thesetonand tune ina TV station.
Connect the VTVM and adjust A9, A10, All andA12 as in steps 6 and7 under "Sound IF alignmentusing AM signal generator and VTVM".
PERM1SSABLE VARIATION
N-rHfr-
FIG.I
F IG.2
FIG3
PAGE 6

ALIGNMENT INSTRUCTIONS (cont)
OSCILLATOR ADJUSTMENT
Leavebiasconnected as under Video IF alignment
Connect the synchronizedsweepvoltage Irom the sweep generator tothe horizontal input ofthe oscilloscope lor horizontal deflection.
The sweepgenerator output lead should be terminated with its characteristic impedance,usually 50 ohms.
Set the fine tuning control to the mid-position of its range.
DUMMY
ANTENNA
Two 1200
Carbon
Resistors
SWEEP
GENERATOR
COUPLING
Across antenna ter-
minals with 12013 in
each lead.
SWEEP
GENERATOR
FREQUENCY
213MC
(10MC Swp)
207MC
(10MC Swp)
201MC
(10MC Swp)
195MC
flOMC Swp)
189MC
OOMC Swp)
183MC
(10MC SWD)
177MC
(10MC Swp)
85MC
(10MC Swp)
79MC
(10MC Swp)
69MC
ilOMC Swp)
63MC
(lOMCSwp)
57MC
(10MC Swp)
MARKER
GENERATOR
FREQUENCY
211.25MC
215.75MC
205.25MC
209.75MC
199.25MC
203.75MC
193.25MC
197.75MC
187.25MC
191.75MC
181.25MC
185.75MC
175.25MC
179.75MC
83.25MC
87.75MC
77.25MC
81. 7 SMC
67.25MC
71.75MC
61.25MC
65.75MC
55.25MC
59.75MC
CHANNEL
13
12
11
10
9
8
7
6
5
4
3
2
CONNECT
SCOPE
Vert. Amp. thru
10KS2 resistor to
point GO . Low side
to chassis.
ADJUST
A13
AM
REMARKS
Adjust to place soundmarker inthe trap
notch asin Fig. 5.
RFAND MIXER ALIGNMENT
The RFand mixerportion of this receiver has beenproperlyaligned atthe factory andis very stable. Alignment of this portionshould not
be attempted inthe field.
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FIG.4
F IG.5
PAGE 7