Checking The Control Circuit Of Vertical Sync Pulse - NEC MultiSync LCD1550V Service Manual

8.2 Checking the control circuit of vertical sync pulse

Check the vertical sync signal on U1 pin 11
at TTL level.
NG
OK
Proceed section 9 "Checking the resolution
change IC movement".
1) No separate sync output signal from the host.(Check the
host.)
2) Video cable may have failed.
3) Printed wire broke between CN1 pin 14 and U1 pin 11.
4) R10 open.
5) U1 failure
6-13
Failure point