![HP F1523 - Pavilion - 15](http://html.mh-extra.com/html/hp/f1523-pavilion-15-lcd-monitor/f1523-pavilion-15-lcd-monitor_service-manual_159601018.webp)
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vf15 / FP15 / f1523 / FP5315
3. Checking the back light unit
Is +12V supplied to CN101
pin 1, 2 to inverter PWB?
OK
NG
Failure point
Inverter cable disconnection.
Check the INV_EN signal input to Inverter Board Q104 at TTL high level.
OK
NG
Is a "H" level being output in the TTL level from I303 pin 114
Or, is INV_EN signal being output?
NG
Failure point
Printed wire broke between I303 pin 114
and Inverter Board Q104.
Check the PWM signal of the input from I303 pin 40 is a BRI signal
OK
NG
Failure point
1)Printed wire broke between
I303 pin 40 and Q313, Q312.
2)I303 failure
Failure point
1) Inverter of LCD module failure.