LG CMS4750F Service Manual page 33

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 IC201 on MAIN board.
5-4-2. How to troubleshoot (Countermeasure)
1) Check AUX_L/R signals to IC201 (Pin23, 24).
2) Check if MCS_BCK, MCS_LRCK & MCS_MCLK are entered from IC501 to IC201.
3) Check if ADC_DATA is entered from IC201 to IC501.
  If no signal, check +5 V & +3.3 V(ADC) for IC201. If is NG, replace it a new one.
4) Check the following I2S 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.
5-4-3. Service hint (Any picture / Remark)
IC201
AUX CS5346
AUX _L/R
12.288 MHZ
PWM
TAS5548
< AUX function signal fl ow >
ONE POINT REPAIR GUIDE
DSP IC501
MLC3730
176PIN BGA
Audio DSP-1
USB 2.0 OTG
SRAM29KB
Main Processor
DSP
Audio DSP-0
I-Cache 8KB
USB 1.1 133Mhz
16KB SRAM29KB
ARM DSP
Host/Device
D-Cache 8KB
I-Cache
926EJS
I-Cache 8KB
133Mhz
16KB
400Mhz
SRAM (10K)
D-Cache 8KB
D-Cache
I2S (7.1ch)
SDRAM
Controller Boot ROM (20KB) GDMA 2ch
SPDIF (Rx, Tx)
Interrupt
ADPCM
controller
CDROM x8 speed
Decoder PLL
ADC (12bit*5ch) RTC & Wake up
GDMA 3ch Clock Controller
Timer, Watchdog UART 4ch (Max)
Reset Controller
NAND Controller GPIO (72 Max) I2C 2ch
within BCH codec
Test Controller
14bits ECC SPI 4ch (Max) SDHC-SDIO 4ch (Max)
FR,FL
TAS5631B
Woofer
TAS5631B
MCS_MCLK to R220
AUX_R to R227
AUX_L to R226
ADC_DATA to R215
< Signal check point >
3-14
MCS_LRCK to R219
MCS_BCK to R216