LG RAT376B Service Manual page 34

NO SOUND
There is no sound output in the TUNER FUNCTION, repair the set according to the
following guide.
5-5. IN THE TUNER FUNCTION
5-5-1. Solution
Please check and replace IC401, TU100 on MAIN board.
5-5-2. How to troubleshoot (Countermeasure)
1) Check if TUNER_LR is entered from Pin1,3 of TU100 to IC401(Pin23, 24).
If no signals, Check +3.3 V for Tuner power.
Check if the Tuner control signals (CLK, DAT, CE, RST, SLT) are entered from IC102 to TU100.
If it doesn't work, replace TUNER with a new one.
2) Check if DAC_BCK, DAC_LRCK, & DAC_MCLK are entered from IC501 to IC202.
3) Check if ADC_DATA is entered from IC401 to IC801.
If no signal, check +5 V & +3.3 V(ADC) for IC401. If is NG, replace it a new one.
4) Check the following I2S audio signal flow from IC801 to IC602. (Refer to Item 5-1.)
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 on Item 5-2.
If AMP is damaged, replace it with a new one.
5-5-3. Service hint (Any picture / Remark)
TUNER_L/R
IC401
CS5346
DAC_MCLK ADC_DATA
DAC_BCK
DAC_LRCK
IC801
MLC9800
DAC_DATA
DAC_MCLK
< TUNER IN function signal fl ow >
ONE POINT REPAIR GUIDE
TUNER
IC602
AMP IC
PS9850
TAS5612
PWM
3-15
< Signal check point >