LG SPH4B-W Service Manual

3-10
Copyright © 2021 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
NO SOUND
2-2. OPTICAL
2-2-1. Solution
Replace MAIN board.
2-2-2. How to troubleshoot (Countermeasure)
1) Please check 3.3 VA.
2) If 3.3 VA is ok, please check OPT_IN signal (C548) when OPTICAL mode.
3) If signal is abnormal, replace MAIN board.
2-2-3. Service hint (Any picture / Remark)
< MAIN board top view >
1
2
R405 R407
R408
R409
R3A3 R3A4 R3A5 R3A6
CN402
X401
F300
F301
C431
C432
C433
C434
C435
C436
C437
C438 C439
C440
C446
L302
FM
RR503
RR505 RR506 RR507 RR508 RR509
RR510
RR511
RR512 RR513 RR514 RR515 RR516 RR517
FB303
F
B
R303
FB314
FB316
JK502
R310
R315
RC502
RC503
RC504 RC505 RC506
RC509
RC510
RC511
RC512
CN502
RC513 RC514 RC515
RC516
CN506
RC517
RC518 RC519
R528
RC522 RC523
C300
R4C3
C307
C308
C31
0
5
40
R
541
C312
C313
C3
1
R549
C4A4
C320
C4A5
C4A6
C323
C331
C333
R370
C334
R371
R375
R380R381
TP_GND
C547
C548
WR505 WR506 WR507 WR508 WR509
WR510
WR511
WR512 WR513
C379
L406
L407
C381
C382
IC302
C383
IC310
C391
WC502
C392
C393
IC313
WC503
C394
WC504 WC505 WC506
WC509
WC513
WC514 WC515 WC519
RFB501
WC520 WC522 WC523
R4N4
FB401
R4N5
FB402
FB403
FB404
R4N8
IC402
Rear SPK
OPTICAL JACK,96KHz
R528
100
3.3VA
OPT_IN
DGND
R549
82
C548
15pF
C547
1uF
JK502
EAG37842010
1
OUT
2
GND
3
VCC
OPTICAL
C548
C548
JK502
JK502

LG SPH4B-W Specifications

General

Brand	LG
Model	SPH4B-W
Category	Speaker System
Language	English