LG OM7560 Service Manual page 40

NO SOUND
There is no sound output in the Bluetooth function, repair the set according to the following guide.
6-8. BLUETOOTH FUNCTION
6-8-1. Solution
Replace IC501 on the MAIN board or bluetooth module on the FRONT Panel.
6-8-2. How to troubleshoot (Countermeasure)
1) Check BT_RX, BT_TX signal to pin6, 4 of CN504.
  If no signal, check the signal to pin4, 6 and pin10 (BT_3.3V) of on the Bluetooth module
and cable connection state.
  If there are no signal out from module, replace new module.
2) Check if BT_RX/TX is entered from pin6, 4 of CN504 to pin L1,K1 to IC501 (DSP).
3) Check if MCS_BCK, MCS_LRCK & MIX_DATA IN is entered from IC501 to IC601.
  If no signal, check +3.3 VA & +1.2 VA for IC501.
If it is abnormal, change replace it a new one.
4) Check the following I2S signal flow from IC501 to IC601.
  If there is any trouble, check the power for each IC.
If the signals are abnormal, replace it a new one.
5) Check if the digital audio AMP block is okay. Refer to "Digital Audio AMP" guide on item 6-1.
  If AMP is damaged, replace it with a new one.
6-8-3. Service hint (Any picture/ Remark)
B/T Module
BT_RX,
BT_TX
IC501
MLC3730
MCS_BCK
MCS_LRCK
MIX_DATA0_OUT
< Bluetooth function signal fl ow >
ONE POINT REPAIR GUIDE
IC601
TPS5548DGG
PWM
TPS5631B
AMP
3-21
< MAIN board bottom view >