Checking The Control Circuit Of Vertical Sync Pulse For Vga - Acer AL1716 Service Manual

4.8 Checking the control circuit of vertical sync pulse for VGA

Check the vertical sync signal on P302
pin14 TTL level
OK
Check the vertical sync
signal on I306 pin90 TTL level
OK
Proceed 'Checking the resolution change IC
movement' section
7. Troubleshooting (continued)
Failure Point:
NG VGA video cables is failure.
Failure Point:
1. Printed wire is open between P302 pin14 and I306
pin90.
NG
2. FB312 and R322 may be open.
3. R323 and C327 may be short.
4. D305, D306 is short.
ACER AL1716W 21
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