LG CMS4540F/W Service Manual

3-11
ONE POINT REPAIR GUIDE
5. NO SOUND
There is no sound output in the CD FUNCTION, repair the set according to the follow-
ing guide.
5-1. IN THE CD FUNCTION
5-1-1. Solution
Please check and replace IC501, IC601 on MAIN board.
5-1-2. How to troubleshoot (Countermeasure)
1) Check CD_BCLK, CD_LRCK, & CD_DOUTA signals from IC407 to IC501.
 If no signal, check if the RF & servo signals from MD is entered to IC407.
Refer to the “No operation of MD” guide on Item 4.
2) Check the following I2S signal flow. < I2S audio signal Interface >
- DAC_BCK : IC501_Pin E1 --> IC601_Pin23
- DAC_LRCK : IC501_Pin D1 --> IC601_Pin22 (44.1 kHz)
- DAC_DATA : IC501_Pin E2 --> IC601_Pin24
- DAC_MCLK : IC501_Pin D2 --> IC401_Pin44
 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.
3) Check if “Digital audio AMP block” on Item 5-2 is normal.
5-1-3. Service hint (Any picture / Remark)
MCS_MCLK (16.93MHz)
MCS_BCK(1.4MHz)
MCS_DATA_OUT
MCS_LRCK(44.1KHz)
M
P/UP
PWM
TAS5548
TAS5612LA
FR,FL
Woofer
12.288MHZ
TAS5612LA
IC407
LC78615E
(New)
DSP IC501
MLC3730
176PIN BGA
< Waveform of I2S audio interface signals >
< I2S Signal Flow >

LG CMS4540F/W Specifications

General

Brand	LG
Model	CMS4540F/W
Category	Stereo System
Language	English