5. Troubleshooting (continued)
5.3.7.2 Checking the control circuit of vertical sync pulse:
5.3.7 Checking the interface circuit of sync signal:
5.3.7.1 Checking the control circuit of horizontal sync pluse:
OK
NG
Failure Point
VGA Video cable is failure.
OK
NG
Failure Point
1) Printed wire broke between CN302
pin 13 and I306 pin 16.
2) L307 or R324 is open.
3) R327 or C325 is short.
Failure Point
Process "Checking the resolution change IC
movement" section.
Check the horizontal sync signal
on CN302 pin 13 TTL level.
Check the horizontal sync signal
on I306 pin 16 TTL level.
OK
NG
Failure Point
VGA Video cable is failure.
OK
NG
Failure Point
1) Printed wire broke between CN302
pin 14 and I306 pin 17.
2) R325 is open.
3) R326 or C324 is short.
Failure Point
Process "Checking the resolution change IC
movement" section.
Check the vertical sync signal
on CN302 pin 14 TTL level.
Check the vertical sync signal
on I306 pin 17 TTL level.
53
ACER A211H/A221HQ