Alignment Instructions - GE Photofact Folder 21C115 Disassembly Instructions Manual

ALIGNMENT INSTRUCTIONS
1.
2.
3.
4.
5.
6.
7.
6.
7.
ALIGNMENT INSTRUCTIONS-READ CAREFULLY BEFORE ATTEMPTING ALIGNMENT
The high voltage shock hazard may be eliminated by removing the horizontal multivibrator tube from its socket.
Allow 20 minute warm-up period for receiver and test equipment.
TRAP ALIGNMENT
Turn the fine tuning control and the contrast control fully clockwise. Turn the volume control and the 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 Vll and V16 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 negative lead of a 4. 5 volt bias supply to pointo^ . Connect positive lead to chassis.
Turn contrast control fully counter clockwise.
Remove the converter tube from its socket and replace with 6J6 which has pin 1 removed. This will disable the local oscillator and reduce the
possibility of erroneous indications.
Connect the synchronized sweep voltage from the sweep generator to the horizontal input of the oscilloscope for horizontal deflection.
DUMMY
ANTENNA
Direct
SWEEP
GENERATOR
COUPLING
High side to an un-
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 A8 for response similar
to Fig. 2. If necessary, retouch A4, AS
and A6 to shape peak region 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 on the schematic.
v
^ ^^
DUMMY
ANTENNA
.01MFD
SIGNAL
GENERATOR
COUPLING
High side to pin 1 (grid)
of 6CB6 (V7) . Low side
to chassis .
"
SIGNAL
GENERATOR
FREQUENCY
4. SMC
(Unmod)
"
CHANNEL
Any non-
interfer-
ing
channel
"
CONNECT ADJUST
VTVM ADJUST
DC probe to point<y> . A9, A10,
Common to chassis. All
DC probe to point &> A12
Common to point &) •
REMARKS
Adjust for maximum deflection.
Adjust for zero reading. A positive and negative read-
ing will be obtained on either side of the correct
setting.
SOUND IF A1IGNMENT USING FM SIGNAL GENERATOR AND OSCILLOSCOPE
Use frequency modulated 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 maximum amplitude and
symmetry as in Fig. 3.
Reconnect stabilizer capacitor C4. Adjust
so that 4. SMC occurs at center of cross-
over lines as in Fig. 4. SLIGHTLY retouch
All for maximum amplitude and stralghtness
of crossover lines .
SOUND IF ALIGNMENT USING TV SIGNAL AND VTVM
Replace Vll and V16.
Remove dummy oscillator tube and replace original 6J6 in its socket
Turn the set on and tune in a TV station.
Connect the VTVM and adjust A9, A10, All and A12 as in steps 6 and 7 under "Sound IF alignment using AM signal generator and VTVM".
PERM1SSABLE VARIATION
N-rHfr-
FIG.I
F IG.2
FIG3
PAGE 6