Sharp LL-153A, Service Manual

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15” LCD Color Monitor Sharp LL-153A
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2.PANEL POWER CIRCUIT
3. INVERTER CONTROL RELATIVE CIRCUIT
NG , no transition
Check R731 should have response from 0V to 5V
When we switch the power switch from on to off
Check the PPWR panel power relative circuit,
Q704(pin2)
In normal operation, when LED =green, R731
should =0 v,
OK
NG, no Voltage
Measured the Q706 pin 3= 5 V?
Replace Q602 ( N-MOS, A03401)
OK
OK
Yes
NG
Check the Bklt-On relative circuit, R711, R712,
In normal operation, when LED =green,
R711,R712 Bklt-On should =5 v,
If Bklt-On no-response when the power switch
turn on-off, Replace U401 TSUM13AK
OK
NG
Replace Power board
& Re-do white balance
Measured the inverter connector
CN701
Pin2 on/off control=5V (on)
Pin4 PWM signal control dim 0V-5V
Replace power board to new-one and check
the screen is normal?
Mea