Abnormal Screen - NEC -FA150ATUA Service Manual

4. Abnormal screen

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 I303 pin 43, 48, 54,
respectively that their level is 0.7Vp-p maximum.
Is the pulse of the TTL level being output to P301-P303
from the data line of I305?
Check the negative horizontal sync pulse output to P301
pin 35 from I305 pin 56 at TTL level.
Check the negative vertical sync pulse output to P301
pin 36 from I305 pin 55 at TTL level.
Check the positive DE pulse output to P301 pin 37 from
I305 pin 54 at TTL level.
Check the SHFCLK OUTPUT to P301 pin 39 from I305
pin 53 at TTL level.
Process "Checking the resolution change IC movement"
N G
O K
N G
O K
N G
O K
N G
O K
N G
O K
N G
O K
N G
O K
section.
Failure point
1) No R, G and B video signal output from host computer. Check
computer
2) Video signal cable disconnection.
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 I303 pin 54.
2) R305 short.
3) C325 open.
4) R304 open.
Failure point
1) Printed wire broke between I305 data line and P301, P303
2) I305 failure.
Failure point
1) Printed wire broke between I305 pin 56 and P301 pin 35.
2) R325 open
3) C386 short
Failure point
1) Printed wire broke between I305 pin 55 and P301 pin 36.
2) R326 open
3) C387 short
Failure point
1) Printed wire broke between I305 pin 54 and P301 pin 37.
2) R327 open
3) C388 short
Failure point
1) Printed wire broke between I305 pin 53 and P301 pin 39.
2) FB311 open
3) FB312 open
4) C390 short
5) C391 short
NEC-FA150ATUA
Trouble Shooting