LG CJ87 Service Manual page 50

NO SOUND
There is no sound output in the TUNER function, repair the set according to the following guide.
9-3. TUNER FUNCTION
9-3-1. Solution
Replace IC200, TU500 on MAIN board.
9-3-2. How to troubleshoot (Countermeasure)
1) Check if TUNER_LR is entered from pin1 & pin3 of TU200 to IC200(pin1, pin2).
  If no signals, check +3.3 V for tuner power.
  Check if the tuner control signals(CLK, DAT, CE, RST, GPO2) are entered from IC501 to TU200.
If it doesn't work, replace TUNER with a new one.
2) Check if MCS_BCK, MCS_LRCK & MCS_MCLK are entered from IC501 to IC200.
3) Check if ADC_DATA is entered from IC200 to IC501.
  If no signal, check +3.3 V(ADC) for IC200. If is NG, replace it a new one.
4) Check the following I2S audio 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.
5) Check if the digital audio AMP block is okay.
  If AMP is damaged, replace it with a new one.
9-3-3. Service hint (Any picture/ Remark)
T-
TUNER_L/R
IC200
ADC_DATA
MCS_MCLK
IC501
MCS_BCK
MCS_LRCK
MIX_DATA_OUT
IC600
PWM
< TUNER function signal fl ow diagram >
ONE POINT REPAIR GUIDE
TUNER
IR AMP
IC200 IC200
TUNER_L to pin26 TUNER_L to pin26
TUNER_R to pin27 TUNER_R to pin27
< MAIN board top view >
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