LG CMS9540F Service Manual

3-3
ONE POINT REPAIR GUIDE
NO POWER
If the unit doesn’t work by no ±PVDD problem, repair the set according to the following
guide.
1-2. NO AMP POWER
1-2-1. Solution
Please check and replace F911, Q905, Q906 on SMPS board.
1-2-2. How to troubleshoot (Countermeasure)
1) Check if the fuse F901 is open or short-circuit.
2) Check the Drain-Source or Drain-Gate, Gate-Source Resistance of Q905, Q906 with a digital multi-meter.
 If it is short condition, it’s destroyed. Replace it with a new one.
(Please replace 2 FET at the same time although several FET is OK)
1-2-3. Service hint (Any picture / Remark)
W3
W2
W1
D932
SMFB14
D934
SMFB14
D935
SMFB14
D921
1SS355
D922
1SS355
D926
SMFB14
ZD912
READY
ZD904
BZX84-C16
ZD915
BZX84-C10
NC
ZD917
READY
C943
22nF
C935
470nF
/50V
C977
10nF
C978
102PF
C979
102PF
C982
READY
C938
68PF
1KV/125C
C933
10nF
C960 1u
F
C972
READY
C932
READY
GND
PFC_OUT
380V
PFC_TH
TH912
BG
12
TH913
0
TH914
PFC_PTC_SMD
FH912
12
FH911
12
P.GND
P.GND
P.GND
P.GND
P.GND
P.GND
P.GND
P.GND
T902
CM9720 PULSE
1 56
7 10
4
IC902
ICE1HS01G-1
1
FMIN
2
CS
3
FB
4
VINS
5
GND
6
LG
7
HG
8
VCC
Q905
IPA60R190E6
1G
3S
2D
Q906
IPA60R190E6
1G
3S
2D
F911
6.3A/250V
TP32
TP38
TP39
TP41
TP42
TP43
TP46
TP47
TP48
TP60
TP61
TP62
TP63
TP64
TP65
PC90
3
2
3
R980
R944
1M
R945
1M
R942
1M
R9A3
1M
R9A6
1M
R941
24K
1%
R950
10K
R949
22
R9B4
0OHM
R9A7
150
1W
R9B9
10K
R9B7
100
R9B8
4.7
R990
10K
R986
100
R988
4.7
R992
3.3
R993
3.3
R9A8
75
12
50X15
HS904
1
2
3
4
BC915
UBW2012-121F
BC911
UBW2012-121F
C934
0.039uF
1250V
C992
READY
C993
READY
T903
4
2
6
7
11
12
13
14
15
16
17
18
19
20
3
5
8
R927
2.7K
12
R951
12K
12
R9C4
12
C940
10nF
C939
22nF
C942
100nF
!
!
R951:24K=> 65KHZ
R951:20K=> 70KHZ
R951 15K 100KHZ
22k VINS :285V
ON/OFF:11.3~12.7V
FBH:4.5V OVERLOAD
Fixed Blanking Time:20ms
VCSL:0.8V
VCSH:1.63V
HS905 H/S
27T/8T:2T
230uH:65uH
25deg >330ohm
Vab:5V
Vth:1.25V
MARK:G2
Ivcc:5.8mA
70deg->2.2kohm
24k VINS :260V
< F911 >
If F911 is not short-circuit,
replace it with a same specifi cations one.
< Q905, Q906 >
If Q905, Q906 is short-circuit,
replace it with a new one.

LG CMS9540F Specifications

General

Brand	LG
Model	CMS9540F
Category	Stereo System
Language	English