NEC MultiSync 20WGX2 Series, Service Manual

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6 - 6
4. Abnormal Screen
OK
NG
Failure point
1) No R, G and B video signal output from
host computer. Check computer
2) Video signal cable disconnection.
NG
Failure point
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
I308 pin 128, 129.
OK
OK
NG
Process "8. Checking the resolution change IC
movement" section.
Failure point
1) I308, I311, I312 failure.
2) Printed wire broken between I308 and
I311, I321.
3) Printed wire broken between I311, I312
and P305.
Check the R, G, B video signal from
computer input on D-Sub R, G, B
connector.
Check the R, G, B input signals on I308
pin 139, 142, 144 respectively that their
level is 0.7Vp-p maximum.
Check all LVDS signal pins, output from
I308, I311, I312.