HP WF1907 Service Manual page 13

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Check the 3.3V power are supplied on I302 pin 2, 4.
OK
Check the 1.8V power are supplied on I303 pin 2, 4.
OK
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Check if the voltage on I302 pin 3 that is
NG
Failure Point
I302 is failure.
Check if the voltage on I303 pin 3 that is
NG
power DC at 3.3V from the I302.
Failure Point
I303 is failure.
power DC at 5V.
NG
OK
NG
OK
Page 12
Failure Point
1) Printed wire broke between P301 pin 5, 6
and I302.
2) FB301, FB302 are open.
3) Check power board.
Failure Point
1) Printed wire broke between I302 pin 2, 4
and I303 pin 3.
2) I302 is failure.