LG SPH4B-W Service Manual

3-9
Copyright © 2021 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
R408
R409
R5A0
R5A1
R5A2
R5A6R5A7
OP5
OP6
OP7
C437
C440
ZD511
ZD512
FL500
RR503
RR505 RR506 RR507 RR508 RR509
RR510
RR511
RR512 RR513 RR514 RR515 RR516 RR517
FB306
FB3
1
FB314
FB509
FB316
R507
R314
R508 R509
R319
RC502
RC503
R510
RC504 RC505
R512
RC506
R514
RC509
R515
R516
R519
RC510
C
RC511
RC512
CN5
0
RC513
CN503
RC514
CN504
R520
RC515
RC516
CN506
RC517
RC518 RC519
R525
R526
R529
RC522 RC523
R531
R532
R533
C304
R534
R540
R541
C505
R542
C506
R543
R544
R547
R548
C510
MCLK
C513
R550
R551
C519
R555
R560
C331
WFB501
R562
C333
R563
C334
R564 R565
C335
R566
R568 R569
R574
R575
R576
OCP
R578
R579
R580
C544
R581
C545
R582
C546
R583
R585
R586
WR503
WR505 WR506 WR507 WR508 WR509
C552
C555
C556 C557
WR510
R594
WR511
R595
WR512
R596
WR513
R597
WR514
C368
R598
WR515
R599
WR516 WR517
D502
D503
C569
C570
C381
C382
C383
IC303
IC306
C387
C388
IC310
C391
WC502
C392
IC313
WC503 WC504 WC505 WC506
WC509
WC510
WC511
WC512 WC513 WC514 WC515
WC516
WC517
WC518 WC519
RFB501
WC520 WC522 WC523
Rear SPK
Subwoofer
JK501
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

LG SPH4B-W Specifications

General

Brand	LG
Model	SPH4B-W
Category	Speaker System
Language	English