LG CM9750 Service Manual page 50

ELECTRICAL TROUBLESHOOTING GUIDE
PORTABLE FUNCTION
IC201
pin9, 10 PT_L/R input signal
OK?
YES
IC201
pin42, 43, 44 I2S input signal
OK?
YES
IC201 pin41
ADC_DATA_IN output signal
OK?
YES
A
TUNER FUNCTION
IC201 pin26, 27
TUNER_L/R input signal
OK?
YES
IC201
pin42, 43, 44 I2S input
signal OK?
YES
IC201
pin41 ADC_DATA_IN output
signal OK?
YES
A
NO
Check FRONT board.
NO
NO
TU500
NO
TUNER_L/R output
signal OK?
NO
Check IC501.
NO
Replace IC201.
3-31
Check IC501.
Replace IC201.
NO
YES
Check +3.3 V of TU500.