LG OK99, Руководство по обслуживанию

Страница: 45 / 85

3-20 Copyright © 2018 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
There is no sound output in the PORT. IN function, repair the set according to the following guide.
10-2. PORT. IN FUNCTION
10-2-1. Solution
Replace IC301 on MAIN board.
10-2-2. How to troubleshoot (Countermeasure)
1) Check PT_L/R signal from TOP board to MAIN board.
2) Check if PT_LR is entered pin2 & 3 of JK303.
3) Check PT_L/R signals to IC301(pin29, 30).
4) Check if DSPI_BCK, DSPI_LRCK & DSPI_MCLK are entered from IC501 to IC301.
5) Check if ADC_DATA is entered from IC301 to IC501.
 If no signal, check DVCC_3.3V & AVCC_3.3V(ADC) for IC301. If is NG, replace it a new one.
6) Check the following I2S signal flow from IC501 to IC601.
 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.
10-2-3. Service hint (Any picture / Remark)
T-
IC501
IC601
PWM
MCS_BCK
MCS_LRCK
T
IC201
POT. IN
ADC_DATA DSPI_MCLK
PTB_L/R
JACK
BOARD
IR AMP
MIX_DATA_OUT
< PORT. IN function signal fl ow > < MAIN board bottom view >
IC301 IC301
IC601 IC601
PT_L to pin29 PT_L to pin29
PT_R to pin30 PT_R to pin30