Circuit Adjustments; Preparation; C Board Adjustment; A Board Adjustment - Sony SSM-Q177 Service Manual

4-1. PREPARATION

Tools required
• Pattern generator
• Oscilloscope

4-2. C BOARD ADJUSTMENT

4-2-1. Sub Brightness Adjustment (RV702)
Note : If CRT is replaced, adjust follows.
(For SSM-Q177)
1. Receive a monoscope signal. (Use TSG-100/MTSG-
1000 Pattern generator SONY Corp.)
2. BRIGHT control ........................... maximum
CONTRAST control ..................... maximum
3. Adjust RV702 so that 40 IRE part in 10 step grey scale
may light dimly and that 20 IRE part may cut-off.
<Monoscope signal>
0 2 4 6 8
1
3
5
7
9
10 step grey scale
0 2 4 6 8
20 IRE (cut-off)
SSM-Q177/Q177CE
SECTION 4

CIRCUIT ADJUSTMENTS

60 IRE
80 IRE
100 IRE
40 IRE (light dimly)
(For SSM-Q177CE)
1. Receive a 10 step stair case (grey scale) signal.
2. BRIGHT control ........................... maximum
CONTRAST control ..................... maximum
3. Adjust RV702 so that 40 IRE part in 10 step grey scale
may light dimly and that 20 IRE part may cut-off.
<STAIR CASE>
40 IRE (light dimly)

4-3. A BOARD ADJUSTMENT

4-3-1. H. Hold (RV402)
Note : If semiconductors for oscillation and
synchronizing circuit, or RV402 are replaced,
adjust as follows
1. Receive a color-bar signal.
2. CONTRAST control ..................... 50%
BRIGHT control ........................... 80%
H-HOLD control ........................... mechanical center
3. Connect the electrolytic capacitor (10 µ F/25 V)
between the pin No.1 of IC401 and GND.
4. Adjust RV402 so that disturbance on the screen stops.
5. Remove the electrolytic capacitor from IC401.
R309 C309
electrolytic
capacitor
(10 µF/25 V)
fo : too low fo : suitable
20 IRE (cut-off)
IC401
1
fo : too high
4-1