HP WF1907 Service Manual page 17

4.4.2 Abnormal screen for DVI source
Check the TMDS signal from computer input on
P303 of DVI-D video connector.
OK
Check the HP output signal to P303 pin 16
respectively that voltage is 4.0 to 5 V.
OK
Check the TMDS input video signals on I306 pin
72, 73, 75, 76, 80, 81, 83, 84 respectively that
their differential input voltage is 150 to 1200 mV.
OK
Check all LVDS signals being output to P306
from I306?
OK
Prpcess "Checking the resolution change IC
movement" section.
NG
Failure Point
1) No TMDS signals output from host computer,
check computer.
2) DVI-D video signal cable disconnection.
Failure Point
The HP is high will to generated TMDS from PC
host.
1) Check P303 pin 14 if is 5V.
2) Printed wire broke between P303 pin 14 and
NG
Q305.
3) C343, C344 is short.
4) Q305 is failure.
5) DVI-D cable is failure.
6) Printed wire broke between Q305 and I306 pin
86.
7) R361 is open. Q305 is failure.
8) I306 is failure.
Failure Point
NG
In the case of the RX2+/- signal. (A RX1, 0, and
RXC signal is the same path, too.)
1) Printed wire broke between P303 pin 1, 2 and
I306 pin 72, 73.
2) DVI-D video cable is failure.
3) R332, R333 is open.
NG
Failure Point
1) Printed wire broke between I306 and P306.
2) LVDS cable failure.
Page 16