LG CK57 Service Manual page 51

NO SOUND
There is no sound output in the AUX FUNCTION, repair the set according to the following guide.
5-4. IN THE AUX FUNCTION
5-4-1. Solution
Please check and replace IC202 on MAIN board.
5-4-2. How to troubleshoot (Countermeasure)
1) Check AUX_L/R signals to IC202 (Pin27, 28).
2) Check if MCS_BCK, MCS_LRCK & MCS_MCLK are entered from IC500 to IC202.
3) Check if ADC_DATA is entered from IC202 to IC500.
 If no signal, check AVCC_3.3V & DVCC_3.3V for IC202. If is NG, replace it a new one.
4) Check the following I2S 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.
5-4-3. Service hint (Any picture / Remark)
( +3. 3V_C D , VC C 1. 2)
PW M
I C 700
PW M + AM P Bl ock
[CK57 : Total 2.1ch 1100W
350+350+400]
[CK56 : Total 2ch 700W]
< AUX function signal fl ow >
ONE POINT REPAIR GUIDE
I I C 501
I C 202
M ai n D SP
LPF
FR O N T( BTL)
AM P
I C 702
FR O N T( BTL)
CK57 Only
LPF
SW(PBTL)
AM P
I c701
AU X I N
IC202 IC202
BCK BCK
< MAIN board top view >
3-14
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AUX_R/ AUX_L AUX_R/ AUX_L
ADC_D/ ATA_IN ADC_D/ ATA_IN
LRCK LRCK
Only for training and service purposes.