3-9
Copyright © 2019 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
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)
< MAIN board top view >
1
R 4 0 8
R 4 0 9
R 5 A 0
R 5 A 1
R 5 A 2
R5A6
R5A7
OP5
O P 6
OP7
C437
C 4 4 0
Z D 5 1 1
Z D 5 1 2
FL500
R R 5 0 3
RR505
RR506
RR507
RR508
RR509
RR510
RR511
RR512
RR513
RR514
RR515
RR516
RR517
FB306
FB3
1
F B 3 1 4
FB509
F B 3 1 6
R 5 0 7
R 3 1 4
R508
R509
R 3 1 9
RC502
RC503
R 5 1 0
RC504
RC505
R512
RC506
R514
RC509
R 5 1 5
R516
R 5 1 9
RC510
C
RC511
RC512
CN50
RC513
C N 5 0 3
RC514
C N 5 0 4
R 5 2 0
RC515
R C 5 1 6
CN506
R C 5 1 7
RC518
RC519
R 5 2 5
R 5 2 6
R 5 2 9
RC522
RC523
R 5 3 1
R 5 3 2
R533
C 3 0 4
R534
R 5 4 0
R 5 4 1
C505
R 5 4 2
C 5 0 6
R 5 4 3
R 5 4 4
R 5 4 7
R 5 4 8
C510
M C L K
C513
R550
R551
C 5 1 9
R555
R560
C 3 3 1
WFB501
R562
C 3 3 3
R563
C 3 3 4
R564
R565
C335
R566
R568
R569
R 5 7 4
R 5 7 5
R 5 7 6
O C P
R 5 7 8
R 5 7 9
R 5 8 0
C 5 4 4
R 5 8 1
C 5 4 5
R 5 8 2
C 5 4 6
R 5 8 3
R 5 8 5
R 5 8 6
W R 5 0 3
WR505
WR506
WR507
WR508
WR509
C 5 5 2
C 5 5 5
C556
C557
WR510
R594
WR511
R595
WR512
R596
WR513
R597
WR514
C368
R 5 9 8
WR515
R 5 9 9
WR516
WR517
D 5 0 2
D 5 0 3
C 5 6 9
C 5 7 0
C 3 8 1
C 3 8 2
C 3 8 3
I C 3 0 3
IC306
C 3 8 7
C 3 8 8
IC310
C 3 9 1
WC502
C 3 9 2
I C 3 1 3
WC503
WC504
WC505
WC506
WC509
WC510
WC511
WC512
WC513
WC514
WC515
W C 5 1 6
W C 5 1 7
WC518
WC519
RFB501
WC520
WC522
WC523
Rear SPK
Subwoofer
J K 5 0 1
C519
10uF
BT_TX
BT_RST
BT_RX
BT_VCC
C505
10pF
C506
100nF
BT_DAT
BT_CLK
C513
10pF
C514
10pF
C551
10pF
BT_GND
BT_RST
UART_TX
BT_CLK
BT_DAT
UART_RX
DGND
DGND
FB509
C510
100nF
DGND
C552
100nF
R555 1K
ZD511
1
2
3
ZD512
1
2
3
3.3VA
CN504
EAG62611102
1
VDD
2
RESET
3
CTS
4
RTS
5
UART_RX
6
GND
7
UART_TX
8
GND
9
SCL
10
SDA
BLUETOOTH
CN504
CN504