Sound - LG SNC4R Service Manual

2. NO SOUND
2-1. BLUETOOTH
2-1-1. Solution
Replace MAIN board.
2-1-2. How to troubleshoot (Countermeasure)
1) Please check status of Bluetooth cable connection. (at CN504 and BT module)
2) Please check 3.3 VA (at pin1 of CN504).
If 3.3 VA is OK, please check UART_RX, UART_TX, RESET, SCL, SDA, RTS, CST
If no signal, please replace MAIN board.
2-1-3. Service hint (Any picture / Remark)
C 3 8 8
C 3 0 4
C 3 8 7
R 3 1 9
C 5 4 5
C 5 4 6
D 5 0 2
J K 5 0 1
C 5 4 4 C 5 7 0
C 5 6 9
D 5 0 3
ONE POINT REPAIR GUIDE
3.3VA
C510
100nF
ZD511
DGND
BT_RST
R555
DGND
BT_RX
UART_RX
BT_TX
UART_TX
BT_CLK
BT_CLK
BT_DAT
BT_DAT
R 3 1 4
M C L K
R 5 0 7
R 5 9 8
R 5 9 9
O P 6
I C 3 0 3
O C P
R 5 1 0
R 5 A 1
R 5 A 0
R 5 7 9
R 5 A 2
R 5 3 2
R 5 8 0 R 5 8 1
R 5 8 2
R 5 3 1
Z D 5 1 1
C 5 5 2
C 5 1 9
C 5 0 6
Z D 5 1 2
CN504 CN504
C N 5 0 4
< MAIN board top view >
BLUETOOTH
FB509
C519 10uF
CN504
BT_VCC
C506 100nF
1
VDD
BT_RST
ZD512
2
RESET
1K
3
CTS
C552
100nF
4
RTS
5
UART_RX
C513 10pF
6
GND
7
UART_TX
C505 10pF
8
GND
9
SCL
C514 10pF
10 SDA
C551 10pF
BT_GND
EAG62611102
DGND
R 5 2 0
R 5 1 9
R 5 8 6
R 5 8 5
R 5 4 3
R 5 7 5
R 5 7 6
R 5 2 9
R 5 8 3
R 5 1 5
R 5 2 5
R 5 7 4
R 5 2 6
R 5 4 4
R 5 4 2
R 5 4 8
R 5 4 7
C 5 5 5
R 5 7 8
W R 5 0 3
W C 5 1 7
W C 5 1 6
C N 5 0 3
Subwoofer
3-9
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C 3 9 2
R 5 4 0
C 3 9 1
R 5 4 1
C 3 8 1
C 3 8 2
C 3 8 3
F B 3 1 4
R R 5 0 3
R C 5 1 7
R C 5 1 6
CN506
Rear SPK
Only for training and service purposes.
CN50
I C 3 1 3
C 3 3 1
R 4 0 9
C 3 3 3
F B 3 1 6
R 4 0 8
C 3 3 4
C 4 4 0
1