LG TH900 Manual page 14

NO SOUND
There is no sound output in the CD FUNCTION, repair the set according to the following guide.
6-2. CD FUNCTION
6-2-1. Solution
Replace IC501 on MAIN board.
6-2-2. How to troubleshoot (Countermeasure)
1) Check CD_BCK, CD_LRCK, & CD_DATA signals from IC501 to IC401.
  If no signal, check if the RF & servo signals from MD is entered to IC401.
Refer to the "No operation of MD" guide on Item 5.
2) Check the following I2S signal flow. < I2S audio signal Interface >
- MCS_BCK :
- MCS_LRCK :
- MIX_DATA0_OUT :
- MCS_MCLK :
  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.
6-2-3. Service hint (Any picture/ Remark)
< Waveform of I2S audio interface signals >
ONE POINT REPAIR GUIDE
IC501_pin E1 --> IC601_pin23
IC501_pin D1 --> IC601_pin22 (44.1 kHz)
IC501_pin E2 --> IC601_pin24
IC501_pin D2 --> IC201_pin44
< MAIN - CD DSP circuit >
3-15
IC501 IC501
R503 R503
< MAIN board top view >