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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 OPTICAL function, repair the set according to the following guide.
6-9. OPTICAL FUNCTION
6-9-1. Solution
Replace IC304 on the MAIN board.
6-9-2. How to troubleshoot (Countermeasure)
1) Check DSPI_BCK, LRCK, MCLK, ADATA of IC304(pin27, 28, 29, 31).
If no signal, check the signal from JK302 pin1 to IC304 pin1
and cable connection state.
If there are no signal out from JK302, replace new connector and cable.
2) Check if MCS_BCK, MCS_LRCK & MIX_DATA IN is entered from IC501 to IC601.
If no signal, check +3.3 VA & +1.2 VA for IC501.
If it is abnormal, change replace it a new one.
3) Check the following I2S signal flow from IC501 to IC601.
If there is any trouble, check the power for each IC.
If the signals are abnormal, replace it a new one.
4) Check if the digital audio AMP block is okay. Refer to “Digital Audio AMP” guide on item 6-1.
If AMP is damaged, replace it with a new one.
6-9-3. Service hint (Any picture/ Remark)
IC501
IC601
PWM
MCS_BCK
MCS_LRCK
MIX_DATA0_OUT
AMP
JK302
IC304
BT_RX,
BT_TX
< OPTICAL function signal
fl
ow >
< MAIN board top view >
IC304
IC304
Содержание OK75
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