LG NP7550 Music flow P7, Service Manual

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3-9
3. AMP
ELECTRICAL TROUBLESHOOTING GUIDE
Set turns on
but there is no sound.
Connect CN700.
Replace IC501.
(Replace main board assembly)
Check power.
Replace IC501.
(Replace main board assembly)
Replace IC501.
(Replace main board assembly)
Replace IC902.
Replace IC501.
(Replace main board assembly)
Replace L701.
Replace IC700.
Replace IC901.
Check 3.3 V.
(L701)
Is PDN signal LOW?
(Pin19 of IC700)
Check connection
of CN700.
Check I2C of IC700.
(R714, R715)
Does 13 V flow IC700?
(Check pin2,3,34,35)
Check I2S of IC700.
(Pin20, 21, 22)
Is ‘AMP_RST’
HIGH state? (R719)
NO
NO
NO
NO
NO
NO
NO
NO
NO
Check output power.
(Pin5 of IC901)
Check IC501 output.
(R528)
Check switching signal.
(Pin2 of IC902)
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
YES
YES
OK