Checking The Back Light Unit - NEC -FA150ATUA Service Manual

3. Checking the back light unit

Is +12V supplied to P803 pin 3, 4 to inverter
1) Inverter cable disconnection.
2) Inverter of LCD module failure.
Trouble Shooting
P W B ?
Failure point
N G
O K
Inverter cable disconnection.
Check the BLON signal of the rectangle input I307 pin 5 at TTL high level
Is a "H" level being output in the TTL level from I306 pin 22
N G
Or, is BLON signal of the rectangle being output?
O K
Check the Bright signal of the input from I306 pin 1 is a Bright signal.
N G
O K
Failure point
N G
Failure point
Printed wire broke between
I306 pin 22
Failure point
1) Printed wire broke between
I306 pin 1 and I307 pin 7.
2) I307 failure.
NEC-FA150ATUA