LG CMS9540F Service Manual page 39

NO SOUND
There is no sound output in the PORT. IN FUNCTION, repair the set according to the
following guide.
6-3. IN THE PORT. IN FUNCTION
6-3-1. Solution
Please check and replace IC202 on MAIN board.
6-3-2. How to troubleshoot (Countermeasure)
1) Check PT_L/R signal from JOG board to MAIN board.
2) Check if PT_LR is entered pin 4 & 5 of CN3J01
3) Check POT_L/R signals to IC202(pin21, 22).
4) Check if ADC_BCK, ADC_LRCK, & DAC_MCLK are entered from IC501 to IC202.
5) Check if ADC_DATA is entered from IC202 to IC501.
If no signal, check +5 V & +3.3 V(ADC) for IC202. If is NG, replace it a new one.
6) Check the following I2S signal flow from IC501 to IC600.
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.
7) Check if the digital audio AMP block is okay. Refer to "Digital Audio AMP" guide.
If AMP is damaged, replace it with a new one.
6-3-3. Service hint (Any picture / Remark)
POT_L/R
IC202
CS5346
ADC/MIC_DATA
MCS_MCLK
MCS_BCK
IC501
MCS_LRCK
MLC3730
MIX_DATA_OUT
< PORT. IN function signal fl ow >
ONE POINT REPAIR GUIDE
POT. IN
VOLUME
Board
IC600
IR AMP
TAS5548
IRS2092+IRF6775
PWM
pin 4 & 5 of CN3V02
3-18
Pin21 & 20 of CN3V01.
< Signal check point >