LG OM5541 Service Manual page 25

There is no sound output in the PORTABLE FUNCTION, repair the set according to
the following guide.
(5) IN THE PORTABLE FUNCTION
[ Solution ]
Please check and replace IC201 on MAIN board.
[ How to troubleshoot (Countermeasure) ]
1) Check PT_L/R signals to IC201 (Pin9, 10).
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 NG, replace it a new one.
4) Check the following I2S signal flow from IC501 to IC601. (Refer to item 4-(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 4-(1).
If AMP is damaged, replace it with a new one.
[ Service hint (Any picture / Remark) ]
PTB_L/R
IC201
CS5346
Portable
12.288 MHz
FL ±
TAS5631BPHD
PWM
TAS5548
< PORTABLE function signal fl ow >
ONE POINT REPAIR GUIDE
DSP IC501
MLC3730
176PIN BGA
PTB_L to R229
PTB_R to R228
< Main Board Top view >
3-10