Checking The Back Light Unit - NEC MultiSync LCD1525V Service Manual

3. Checking the back light unit

Is +12V supplied to I101 pin 1 and pin 2, 3.
NG
OK
Is +12V supplied to P309 pin 3, 4 to
inverter PWB?
NG
OK
Check the Uc-PBIAS signal of the rectangle input I104 pin 3 at TTL high level
NG
OK
Check the PWM signal of the input from I201 pin 9 is a PWM signal.
NG
OK
Failure point
1) Inverter cable disconnection.
2) Inverter of LCD module failure.
Are connected AC adapters normal goods?
Failure point
Inverter cable disconnection.
Is a "H" level being output in the TTL level from I201 pin 17
Or, is Uc-PBIAS signal of the rectangle being output?
Failure point
Printed wire broke between
I201 pin 17 and I101 pin 3
1) Printed wire broke between
I201 pin 9 and I104 pin 5.
2) I104 failure.
NG
OK
Printed wire broke between P301
pin 1 and I101 pin 1,2 & 3
NG
Failure point
6-6
Failure point
An AC adapter is changed to the
normal goods.
Failure point