Checking The Back Light Unit - HP VF15 Service Manual

3. Checking the back light unit

Is +12V supplied to CN101
OK
Check the INV_EN signal input to Inverter Board Q104 at TTL high level.
OK
OK
1) Inverter of LCD module failure.
Page 16
pin 1, 2 to inverter PWB?
Failure point
NG
Inverter cable disconnection.
Is a "H" level being output in the TTL level from I303 pin 114
NG
Or, is INV_EN signal being output?
Check the PWM signal of the input from I303 pin 40 is a BRI signal
NG
Failure point
NG
Failure point
Printed wire broke between I303 pin 114
and Inverter Board Q104.
Failure point
1)Printed wire broke between
I303 pin 40 and Q313, Q312.
2)I303 failure
vf15 / FP15 / f1523 / FP5315