LG OK99 Service Manual page 54

ELECTRICAL TROUBLESHOOTING GUIDE
NO AUDIO CHECK
USB play
When insert USB,
IC501 pin U7, U8, A7, A8
USB_D signal OK?
YES
A
AUX
IC301
pin1, 2 AUX input signal
OK?
YES
IC301
pin15, 16, 17 I2S input signal
OK?
YES
IC301
pin18 ADC_data output signal
OK?
YES
A
IC207
NO
USB Power USB_5V
OK?
NO
NO
NO
3-29
NO
YES
Check audio jack.
Check IC501.
Replace IC301.
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Check DRV_VBUS2.0 signal.
Only for training and service purposes.