LG OM7550 Service Manual

3-20
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the AUX function, repair the set according to the following guide.
10-2. AUX FUNCTION
10-2-1. Solution
Replace IC201 on MAIN board.
10-2-2. 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/MIC_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 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.
5) Check if the digital audio AMP block is okay.
 If AMP is damaged, replace it with a new one.
10-2-3. Service hint (Any picture / Remark)
AUX
IC501
MLC3730
IC202
PS9860
PWM
MCS_BCK
MCS_LRCK
IC201
CS5346
ADC/MIC_DATA
MCS_MCLK
AUX_L/R
IR AMP
IRS2092+IRF6775
MIX_DATA_OUT
< AUX function signal fl ow >
< MAIN board bottom view >
IC201
IC201
ADC/MIC_DATA to R212
ADC/MIC_DATA to R212
MCS_BCK to R213
MCS_BCK to R213
MCS_LRCK to R215
MCS_LRCK to R215
MCS_MCLK to R216
MCS_MCLK to R216
AUX_R to R209
AUX_R to R209
AUX_L to R210
AUX_L to R210

LG OM7550 Specifications

General

Brand	LG
Model	OM7550
Category	Stereo System
Language	English