NEC NEC MultiSync LCD1525V LCD1525V LCD1525V, Service Manual

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6-10
OK
NG Failure point
1) C476 or C477 short.
2) I102 failure
3) Disconnection between I102 pin 2 and I402 pin 8, 20 may have failed.
b a
Proceed "Checking the resolution change IC movement" section.
Check the +5V is supply on I402 pin 8, 20.
OK
NG
Check the input of the dot clock on I402 pin 7 at TTL level.
Check the output of the dot clock on I402 pin C8 at TTL level.
OK
NG
Proceed "Checking the resolution change
IC movement" Section.
Check positive
horizontal sync
signal on I402 pin
18 at TTL level. Failure point
1) Printed wire broke between I401 pin C8 and I402 pin 7.
2) C475 open
OK
NG
Check the positive horizontal sync signal on I401 pin B9 at TTL level.
OK
NG
Proceed "Checking the resolution change
IC movement" Section.
Failure point
1) Printed wire broke between I401 pin B9 and I402 pin 18.
2) R443 open
Check negative vertical sync signal on I402 pin 19 at TTL level.
OK
NG
Check negative vertical sync signal on I401 pin E20 at TTL level.
OK
NG
Proceed "Checking the resolution change
IC movement" Section.
Failure point
1) Printed wire broke between I401 pin E20 and I402 pin 19.
2) R444 open
Failure point
I402 failure.