LG CK57 Service Manual page 52

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 IC202 and IC200 on MAIN board.
5-5-2. How to troubleshoot (Countermeasure)
1) Check if TUNER_LR is entered from pin14. 13 of IC 200 to IC202(Pin29, 30).
 If no signals, check AVCC_3.3V for IC200 power.
 Check if the tuner control signals (CLK, DAT, CE, RST, SLT) are entered from IC500 to IC200.
If it doesn't work, replace IC200 with a new one.
2) Check if MCS_BCK, MCS_LRCK, & MCS_MCLK are entered from IC500 to IC202.
3) Check if ADC_DATA_IN is entered from IC202 to IC500.
 If no signal, check AVCC_3.3V & DVCC_3.3V for IC202. If is NG, replace it with a new one.
4) Check the following I2S audio signal flow from IC500 to IC700.
 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.
5-5-3. Service hint (Any picture / Remark)
( +3. 3V_C D , VC C 1. 2)
PW M
I C 700
I C 702
I c701
PW M + AM P Bl ock
[CK57 : Total 2.1ch 1100W
350+350+400]
[CK56 : Total 2ch 700W]
< TUNER IN function signal fl ow >
ONE POINT REPAIR GUIDE
I I C 501
I C 202
M ai n D SP FM/AM
LPF
FR O N T( BTL)
AM P
FR O N T( BTL)
CK57 Only
LPF
SW(PBTL)
AM P
TU N ER
IC202 IC202
( FM / AM )
BCK BCK
< MAIN board top view >
3-15
Copyright © 2018 LG Electronics Inc. All rights reserved.
TUNER_R/ TUNER_L TUNER_R/ TUNER_L
ADC_D/ ATA_IN ADC_D/ ATA_IN
LRCK LRCK
Only for training and service purposes.