5. Troubleshooting (continued)
5.2.7 Checking the interface circuit of sync signal:
5.2.7.1 Checking the control circuit of horizontal sync pluse:
5.2.7.2 Checking the control circuit of vertical sync pluse:
OK
NG
Failure Point
VGA Video cable is failure.
OK
NG
Failure Point
1) Printed wire broke between CN302
pin 13 and I310 pin 22.
2) L306 or R327 is open.
3) R330 or C331 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 I310 pin 22 TTL level.
OK
NG
Failure Point
VGA Video cable is failure.
OK
NG
Failure Point
1) Printed wire broke between CN302
pin 14 and I310 pin 21.
2) R328 is open.
3) R329 or C330 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 I310 pin 21 TTL level.
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ACER A211H/A221HQ