Abnormal Screen - HP VF15 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 I303
pin 171, 167, 163 respectively that their level is 0.7Vp-p
OK
Is the pulse of the TTL level being output to P307, P308
from the data line of I303?
OK
Check pulse of POL/HMS2/HMS1/LP/STH are output to
P308 pin 44, 45, 46, 47, 48 at TTL level.
OK
Check the pulse of CLKV/STV1 are output to P307
OK
Check the CLKH OUTPUT to P308 pin 3 from I303 pin
115 at TTL level.
OK
Process "Checking the resolution change IC movement"
NG 1) No R, G and B video signal output from host computer. Check
2) Video signal cable disconnection.
maximum.
In case of the Red signal. (A Green and Blue signal is the same
NG
path, too.)
1) Printed wire broke between D-Sub(R) and I302 pin 171.
2) R334 short.
3) C339 open.
4) R332 open.
NG
1) Printed wire broke between I303 data line and P307, P308
2) I303 failure.
NG
1) Printed wire broke between I303 and P308 of control line.
2) LZ301~LZ312 open or RP303~RP314 open.
3) CN301~CN312 short
pin 7, 8.
NG
1) Printed wire broke between I303 and P307 of control line.
2) R357, R355 open
3) C394, C393 short
1) Printed wire broke between I303 pin 115 and P308 pin 3.
NG
2) FB324 open
3) FB325 open
4) C401 short
section.
Failure point
computer
Failure point
Failure point
Failure point
Failure point
Failure point
vf15 / FP15 / f1523 / FP5315
Page 17