Sony PVM-20M2U Service Manual page 33

8. Adjustment of burst gate pulse width
1. Input an NTSC color bar.
2. Connect the probe of an oscilloscope to TP301 (COMP-SYNC)
and Q363 (E) or IC305
CD
PIN. (Exercise care since IC305 (1)
PIN is a high-impedance line.)
3. Set the unit in the service mode.
4. Adjust
lBGP WIDTH
I
so that the output waveforms will be as shown
in Fig.5-15.
9. VXO adjustment
9-1. X'tal358
T
Fig. 5-15
1) Input an NTSC color bar.
T=7.8±0.2J.IS
2) Connect a frequency counter to IC305
<D
PIN.
3) Set the unit in the service mode.
4) Connect IC305
CD
PIN as shown in Fig.5-16.
5) Adjust
lNTSC CRYSTAL!
so that the counter reading will be within
the standard values shown below. (Adjustment may be made at a
point at which the color flickering stops.)
X' tal 358 standard vlaue: 3579545±20 Hz
18K
TO IC 305 (i)pin
ISS133 etc
(Arrange 4 Di's as close as possible to
(i)PIN at the shortest possible distance.)
Fig. 5-16
9-2. X'tal 443
1) Input a 443 NTSC color bar.
2) Connect a frequency counter to IC305 <2) PIN.
3) Set the unit in the service mode.
4) Connect IC305
CD
PIN in the same way as 9.-4) in 9. VXO ad-
justment.
5) Adjust
l~NT:::;;S"'C""44~3""CK""Y-:.S""TAL.,.-;"ll
in the same way as 9.-5) in 9. VXO
adjustment.
X'tal443 standard value: 4433619±20 Hz
10. NTSC . NTSC443 . PAL color demodulation adjustment
Note : 10-1. is not applicable to the group of models
3.
10-1. NT358PHASE (NORMAL)
1) Input an NTSC color bar.
2) Connect the probe of an oscilloscope to TP306.
3) Set the unit in the HIV DELAY mode.
4) Set the unit in the service mode.
5) Adjust
I
PHASE NTSC 358 NOR
I
so that the burst section of the out-
put waveform will be straight. (Fig.S-17)
10-2. NT 358 PHASE (ACC OFF)
1) Conduct ACC OFF via MENU.
2) Make adjustment in the same way as 10-1. shown above by means
of
lPHASB NTSC 443 ACC OFF
I.
(Fig.5-17)
Make it flat
Fig. 5·17
10-3. NT 358 B-Y PHASE
Note: Make adjustment after PHASE adjustment
and~efore
CHROMA adjustment.
1) Input an NTSC color bar. (Input only the R-Y component. B-Y
andY should be OFF.)
2) Connect the probe of an oscilloscope to TP305.
3) Set the unit in the service mode.
4) Adjust
I
B-Y PHASE NTSC 3581
so that the color compoaents will be
straight.
10-4. NT 358 CHROMA (NORMAL)
1) Input an NTSC color bar.
2) Connect the probe of an oscilloscope to IC404
~
Pil'oJ orTP402.
3) Set the unit in the service mode.
4) Adjust
lCHR.OMA NTSC 358 NOR!
so that the peaks of ...vaveforms
will be flush with each other as shown in Fig.S-18.
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