LG CM9730 Service Manual page 37

NO SOUND
There is no sound output in the TUNER FUNCTION, repair the set according to the
following guide.
6-5. IN THE TUNER FUNCTION
6-5-1. Solution
Please check and replace IC202, TU801 on MAIN board.
6-5-2. How to troubleshoot (Countermeasure)
1) Check if TUNER_LR is entered from Pin1 & 3 of TU801 to IC202(Pin23, 24).
If no signals, Check +3.3 V for Tuner power.
Check if the Tuner control signals (CLK, DAT, CE, RST, GPO2) are entered from IC101 to TU801.
If it doesn't work, replace TUNER with a new one.
2) Check if ADC_BCK, ADC_LRCK, & DAC_MCLK are entered from IC501 to IC202.
3) 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.
4) Check the following I2S audio signal flow from IC501 to IC600. (Refer to Item 6-1.)
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.
If AMP is damaged, replace it with a new one.
6-5-3. Service hint (Any picture / Remark)
TUNER_L/R
IC202
CS5346
DAC_MCLK ADC_DATA
DAC_BCK
IC501
DAC_LRCK
MLC3700
< TUNER function signal fl ow >
ONE POINT REPAIR GUIDE
TUNER
Jack
Board
IC600 IR AMP
IRS2092+IRF6775
PS9854
PWM
3-20
< Signal check point >