Main Board Failure Check - Haier LE55B1381a Service Manual

Service Manual
Model No.:

9-2. Main board failure check

Power Units Problem Solving
In stand-by condition,
Check pin 10of J5,
Whether got 5V
N
Y
Whether main board testing TP8point got 3.3V?
N
Y
Normal booting
Check U9 power
Check external
network
power suppply
After power on, check
whether pin 3/4 of J5got 5v,
pin 1 of J5 got 12v, testing
point TP7 got 2.5v, testing
point TP3 got 3.3v, testing
point TP5 got 1.8v, testing
point TP1 got 1.32v?
N Y
Whether power suppply and main
OK
board is shortcircuit?
Whether power chip LDO(U3)
works?
power chip LDO(U6) works?
diode (D29) works?
power chip (U1) works?
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