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2. PANEL POWER CIRCUIT
NG
Check C454 should have response from 0V to 5V
When we switch the power switch from off to on
Check U701, Q403 is broken or CN403 solder abnormal?
OK
Replace Panel
3. INVERTER CONTROL RELATIVE CIRCUIT
On/Off control=5V (on)
DIM signal control 0V-5V
Replace Power board
& Re-do white balance
OK
NG
Replace U701, Q403 or re-solder CN403
NG
NG
Measured X401 waveform is normal?
Measured power supply for U401
Check the Bklt-On relative circuit, R201, Q201,
OK
In normal operation, when LED =green,
Base of Q201 should =0 v,
In saving mode, when LED=orange,
Base of Q201 should =5 v,
Page 29 of 44
Lenovo LXM-L19BH
NG
OK
Replace U401
OK
Replace U201
Replace X401
Check power
supply circuit
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