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SECTION 4
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CIRCUIT ADJUSTMENTS
4-1. A BOARD ADJUSTMENTS
TUNER AGC ADJ
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VIF101
@
A BOARD (COMPONENT SIDE)
-
TUNER AGC ADJUSTMENT
(AGC VR
1.
Align with an appropriate signal between stations.
2.
Adjust AGC
VR so that snow
noise and cross
modulation just disappear from the picture.
IFG5.5S SIF
@ @
eT nail
STEREO SEPARATION
RV2
H.FREQ
IFG5.5S SIF -component side-
STEREO SEPALATION ADJUSTMENT
(RV1
1.
Input stereo signals. (L-CH 400Hz, R-CH 1KHz)
2. Check the stereo indicator.
3.
Connect on oscilloscope to pin® (CH1) of CN1
through band pass filter of 1KHz
4.
Adjust RV1 so that 1KHz voltage goes down to
the minmum.
1.
Input a PAL COLOR BAR signal, then connect
a jumper between pin@2
IC4 and GND.
2.
Connect
a frequency counter
to pin@ IFG5.5S
(HP) of CN1 through a probe of 10:1.
Adjust RV2 (H.FREQ) 15.625+50Hz.
4.
After adjustment, remove the jamper.
4-2.
B BOARD ADJUSTMENTS
CT331
REF OSC
CT332
Q335
BELL
B BOARD (COMPONENT SIDE)
REFERENCE OSCILLATOR ADJUSTMENT
(CT332 8.8MHz)
1.
Input a PAL color bar signal.
2.
Ground pin @) of the IC331. -
3.
Adjust CT332 to obtain synchronization.
REFERENCE OSCILLATOR ADJUSTMENT
(CT331_ 7.16MHz)
1.
Input an NTSC358 color bar signal.
2.
Ground pin € of I1C331.
3.
Adjust the CT331 to obtain synchronization.
4.
Remove the jumper grounding pin @% of IC331.
BELL FILTER ADJUSTMENT
(L336
1.
Input a SECAM color bar signal.
2.
Connect the oscilloscope to the emitter of Q335.
3.
Adjust L336 so that the waveform is flat.
eam
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