Checking The Interface Circuit Of Sync Signal; Checking The Control Circuit Of Horizontal Sync Pulse; Checking The Control Circuit Of Vertical Sync Pulse - Acer AL502 Service Manual

7. Checking the interface circuit of sync signal

7.1 Checking the control circuit of horizontal sync pulse

7.2 Checking the control circuit of vertical sync pulse

Trou bl e Sh ooti ng
Check the horizontal sync signal on I301
pin 94 TTL level.
NG
1) Video cable may have failed.
2) Printed wire broke between P302 pin 13
OK
and I301 pin 94
3) R346, R348 open
4) C372, C373 short
Process "Checking the resolution change IC
movement" section.
Check the vertical sync signal on I300 pin
44 TTL level.
NG
1) Video cable may have failed.
OK
2) Printed wire broke between P302 pin 7 and I300 pin 44
3) FB308, R343 open
4) C369 short
Process "Checking the resolution change IC
movement" section.
Failure point
Failure point
A L C502
Page 9