LG OM7550 Service Manual

3-21
< MAIN board bottom view >
IC201
IC201
PT_L to R228
PT_L to R228
PT_R to R227
PT_R to R227
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the PORT. IN function, repair the set according to the following guide.
10-3. PORT. IN FUNCTION
10-3-1. Solution
Replace IC201 on MAIN board.
10-3-2. How to troubleshoot (Countermeasure)
1) Check PT_L/R signal from FRONT board to MAIN board.
2) Check if PT_LR is entered pin1 & 3 of CN201  pin1 & 3 of CNA304.
3) Check PT_L/R signals to IC201(pin9, 10).
4) Check if ADC_BCK, ADC_LRCK & DAC_MCLK are entered from IC501 to IC201.
5) 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.
6) Check the following I2S signal flow from IC501 to IC202.
 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.
7) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide.
 If AMP is damaged, replace it with a new one.
10-3-3. Service hint (Any picture / Remark)
T-
IC501
MLC3730
IC202
PS9860
PWM
MCS_BCK
MCS_LRCK
T
IC201
CS5346
POT. IN
ADC/MIC_DATA
MCS_MCLK
POT_L/R
VOLUME
Board
IR AMP
IRS2092+IRF6775
MIX_DATA_OUT
< PORT. IN function signal fl ow >

LG OM7550 Specifications

General

Brand	LG
Model	OM7550
Category	Stereo System
Language	English