Abnormal Screen - NEC MultiSync LCD1700NX A Service Manual

4. Abnormal Screen

Check the R, G, B video signal from
computer input on D-Sub R, G, B
connector.
OK
Check the R, G, B input signals on
I315 pins E1, D2, C1 respectively that
their level is 0.7Vp-p maximum.
OK
Is the pulse of the TTL level being
output to I319, I320 from the data
line of I315?
OK
Check the negative horizontal
sync pulse output to RN314 pin 8
from I315 pin F20 at TTL level.
OK
Next page
NG
NG
NG
1) Printed wire broke between I315 data line and I319, I320.
2) I315 failure.
NG
1) Printed wire broke between I315 pin F20 and RN314 pin 8.
2) I315 failure.
1) No R, G and B video signal output from host computer.
Check computer
2) Video signal cable disconnection.
In the case of the Red signal. (A Green and Blue signal is
the same path, too.)
1) Printed wire broke between D-Sub(R) and I315 pin E1.
2) R339 short.
3) C359 open.
4) R337 open.
Failure point
Failure point
6-7
Failure point
Failure point