LG OM4560 Service Manual page 31

NO SOUND
There is no sound output in the AUX FUNCTION, repair the set according to the following guide.
5-4. IN THE AUX FUNCTION
5-4-1. Solution
Please check and replace IC202 on MAIN board.
5-4-2. How to troubleshoot (Countermeasure)
1) Check AUX_L/R signals to IC202 (Pin26, 27).
2) Check if MCS_BCK, MCS_LRCK & MCS_MCLK are entered from IC502 to IC202.
3) Check if ADC_DATA is entered from IC202 to IC502.
  If no signal, check +5 V & +3.3 V(ADC) for IC202. If is NG, replace it a new one.
4) Check the following I2S signal flow from IC701 to IC700. (Refer to Item 5-1.)
  If there is any trouble, check the power for each IC.
The power is normal but, if the signal waveform to the IC is distorted or no signal, replace it with a new one.
5) Check if the digital audio AMP block is okay. Refer to "Digital Audio AMP" guide on Item 5-2.
  If AMP is damaged, replace it with a new one.
5-4-3. Service hint (Any picture/ Remark)
< Signal check point - Top PCB >
ONE POINT REPAIR GUIDE
3-14
< AUX function signal fl ow >
< Signal check point - Bottom PCB >