Amp - LG NP7550 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

3. AMP

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