LG CM5660 Service Manual page 36

6. NO SOUND
There is no sound output in the PORTABLE function, repair the set according to the following guide.
6-6. PORTABLE FUNCTION,
6-6-1. Solution
Please check and replace IC202 on MAIN board.
6-6-2. How to troubleshoot (Countermeasure)
1) Check if PT_LR signals to IC202 (pin26, pin27).
2) Check if MCS_BCK, MCS_LRCK, & MCS_MCLK are entered from IC500 to IC201.
3) Check if ADC_DATA is entered from IC201 to IC500.
  If no signal, check DVCC_5V & DVCC_3.3V (ADC) for IC202. If is NG, replace it with a new one.
4) Check the following I2S audio signal flow from IC500 to IC700. (Refer to Item 6-1-2.)
  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 6-2.
  If AMP is damaged, replace it with a new one.
6-6-3. Service hint (Any picture/ Remark)
< PORT. IN function signal fl ow >
ONE POINT REPAIR GUIDE
DSP IC500
PT_L: pin26 PT_L: pin26
PT_R: pin27 PT_R: pin27
3-19
IC202 IC202
< MAIN board top view >