720C/920C
5-1
5 Troubleshooting
5-1 Parts Level Troubleshooting
Notes:
1. If a picture does not appear, fully rotate the brightness and contrast controls clockwise and reinspect.
2. Check the following circuits.
• No raster appears: Power circuit, Horizontal output circuit, H/V control circuit, and H/V output circuit.
• High voltage develops but no raster appears: Video output circuits.
• High voltage does not develop: Horizontal output circuits.
5-1-1 No Power Supply
Check and replace FG601, D601,
IC661, IC662.
Done.
Repeating start?
Check and replace D601, D604, D663,
Q632, and Q664.
No
Yes
IC601 Pin 1 waveform is right?
Check and replace IC601,
IC602, IC604.
Yes
No
IC602 and IC604
are right?
Replace parts and verify voltages.
Yes
No
Normal operation
Replace Main board.
Yes
Yes
No
WAVEFORMS
1
1
544 V (IC601, #1)
CH1 P-P = 544 V
CH1 RMS = 332.4 V
Verify voltages.
Содержание 720C
Страница 33: ...720C 920C 6 1 6 1 720C Exploded View and Parts List ...
Страница 34: ...720C 920C 6 2 6 2 920C Exploded View and Parts Lists ...
Страница 79: ...T601 C639 C609 C636 C638 L601 C604 D637 D608 10 1 Power Parts Schematic Diagram 720C 920C 10 1 ...
Страница 80: ...R299 720C 920C 10 2 10 2 MICOM Parts Schematic Diagram ...
Страница 81: ...720C 920C 10 3 10 3 Horizontal Vertical Processor Parts Schematic Diagram R265 C272 R262 ...
Страница 83: ...R561 R562 R501 C530 L521 R523 R526 720C 920C 10 5 10 5 High Voltage Parts Schematic Diagram ...
Страница 84: ...720C 10 6 1 10 6 1 720C Video Parts Schematic Diagram ...
Страница 86: ...720C 920C 10 7 10 7 Connector and Option Boards Parts Schematic Diagram CN142 slcon4p slcon4p CN141 CN208 ...