Is +20V supplied to inverter PWB ? (by the
power board)
4.3 Checking the back light unit
OK
NG
Failure Point
1) Inverter cable disconnection.
2) Power board failure.
Check the BACKLIGHT_EN signal of the
P301 pin 2 at high level.
OK
NG
Failure Point
1) printed wire broke between P301 pin 2,
R305 and I306 pin 49.
2) R305 is open, or R306, C308 are short.
3) I306 is failure.
Check the BACKLIGHT_ADJ signal of the
P302 pin 3 from I306 pin 50 is a PWM
signal.
OK
NG
Failure Point
1) printed wire broke between P301 pin 3,
Q301 and I306 pin 50.
2) Q301 is failure.
3) R301 or R302 or R304 is open, or C304
is short.
4) I306 is failure.
Failure Point
Back light unit of LCD module is failure.
Page 14
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