Sony GV-A500E, Service Manual

Page: 84 / 127

5-25
3-3. SERVO SYSTEM ADJUSTMENTS
1. CAP FG Offset Adjustment (VC-197 board)
Improve the capstan servo characteristic. If it is not correct, jitters
will increase.
Mode Playback (SP mode)
Signal Alignment tape : For operation check
(WR5-5NSP(NTSC))
(WR5-5CSP(PAL))
Measurement Point Pin
4
of CN207 (CAP FG)
Measuring Instrument Oscilloscope
Adjustment Page F
Adjustment Address 3A
Specified Value Duty = 50 ± 1.5%
Adjusting method:
1)
Set page: 0, address: 01, data: 01.
2) Change the page: F, address: 3A, data by pressing the PLAY
and STOP buttons of the remote commander until the duty
satifies the specification.
3) Press the PAUSE button of the adjusting remote commander.
4) Set page: 0, address: 01, data: 00.
Fig. 5-3-6.
A
B
Duty=A/B
×
100 [%]
Center of movement
2. Switching Position Adjustment (VC-197 board)
If deviated in this case causes switching noise or jitter on the played
back screen.
Mode Playback
Signal Alignment tape:
For tracking adjustment
(WR5-1NP (NTSC))
(WR5-1CP (PAL))
Measurement Point CH1: Pin
3
of CN207 (RF SWP)
CH2: Pin
6
of CN207 (PB RF)
Measuring Instrument Oscilloscope
Adjustment Page F
Adjustment Address 36, 37
Specified Value t1 = 0 ± 10
µ
sec
Note : NTSC model : GV-A500
PAL model : GV-A500E
Adjusting method:
1)
Set page: 0, address: 01, data: 01.
2) Change the data of page: F, address: 37 and minimize “t1”,
and press the PAUSE button of the adjusting remote
commander. (Coarse adjustment)
3) Change the data of page: F, address: 36, and adjust so that the
switching position (t1) becomes the specified value. (Fine
adjustment)
4) Press the PAUSE button of the adjusting remote commander.
5) Set page: 0, address: 01, data: 00.
Fig. 5-3-7.
CH1
CH2
Enlargement
t1=0
±
10
µ
sec
CH1
CH2