LG S90QY Service Manual page 47

PROTECTION ERROR
No display or no sound.
3-2. S(SHUT DOWN) PROTECTION
3-2-1. Solution
Replace AMP board.
3-2-2. How to troubleshoot (Countermeasure)
1) Check PVDD voltage (23.2 V) of IC7001, IC7002, IC7003, IC7004 (easily check the pad of C7204, C7205,
C7215, C7216).
- If PVDD voltage has 8.5 V under, check SMPS.
2) Check impedance (4 Ω) of speaker unit.
- If impedance of speaker unit has 1 Ω under, replace speaker unit.
3) If check point 1), 2), 3) is OK, replace AMP board.
3-3-3. Service hint (Any picture / Remark)
IC7003
1 44
BST1_P
VDD
2 43
BST1_M
GAIN/SLV
3 42
GND_12
OTW_CLIP
4 41
GND_11
FAULT
5 40
OUT1_P_2
GND_1
6 39
OUT1_P_1
GND_2
7 38
TR
PVDD_6
GND_3
8 37
PVDD_5
IN1_P
9 36
PVDD_4
IN1_M
10 35
OUT1_M
RESET
11 34
GND_10
HEAD
12 33
GND_9
OSCM
13 32
OUT2_P
OSCP
14 31
PVDD_3
FREQ_ADJ
15 30
PVDD_2
IN2_P
16 29
SR
PVDD_1
IN2_M
17 28
OUT2_M_2
CMUTE
18 27
OUT2_M_1
GND_4
19 26
GND_5
GND_8
20 25
GND_6 GND_7
21 24
AVDD BST2_P
22 23
GVDD BST2_M
IC7003 IC7003
IC7003 IC7003
C7215 C7215
ONE POINT REPAIR GUIDE
PVDD PVDD
C7215
330uF /35V
IC7004
1 44
C7113 33nF
BST1_P
VDD
2 43
C7114 33nF
BST1_M
GAIN/SLV
3 42
GND_12
OTW_CLIP
4 41
GND_11
FAULT
5 40
OUT1_P_2
GND_1
6 39
OUT1_P_1
GND_2
C7115 1uF 50V
7 38
PVDD_6
GND_3
8 37
FR
PVDD_5
IN1_P
C7116 1uF 50V 9 36
PVDD_4
IN1_M
10 35
OUT1_M
RESET
11 34
GND_10
HEAD
12 33
GND_9
OSCM
13 32
OUT2_P
OSCP
C7117 1uF 50V 14 31
PVDD_3
FREQ_ADJ
15 30
PVDD_2
IN2_P
CT
C7118 1uF 50V
16 29
PVDD_1
IN2_M
17 28
OUT2_M_2
CMUTE
18 27
OUT2_M_1
GND_4
19 26
GND_5
GND_8
20 25
GND_6 GND_7
21 24
C7125 33nF
AVDD BST2_P
22 23
C7126 33nF
GVDD BST2_M
IC7004 IC7004
PGND
IC7004 IC7004
C7216 C7216
< AMP board top view >
PVDD
C7216
IC7001
330uF /35V 330uF /35V
1 44
C7119 33nF C7033 33nF
BST1_P
VDD
2 43
C7120 33nF C7034 33nF
BST1_M
GAIN/SLV
3 42
GND_12
OTW_CLIP
4 41
GND_11
FAULT
5 40
OUT1_P_2
GND_1
CEN
6 39
OUT1_P_1
GND_2
C7121 1uF 50V 7 38 C7035
PVDD_6
GND_3
8 37
PVDD_5
IN1_P
C7122 1uF 50V 9 36 C7036
PVDD_4
IN1_M
10 35
OUT1_M
RESET
11 34
GND_10
HEAD
12 33
GND_9
OSCM
13 32
OUT2_P
OSCP
C7123 14 31
1uF 50V C7037
PVDD_3
FREQ_ADJ
15 30
PVDD_2
IN2_P
FL
C7124
1uF 50V 16 29 C7038
PVDD_1
IN2_M
17 28
OUT2_M_2
CMUTE
18 27
OUT2_M_1
GND_4
19 26
GND_5
GND_8
20 25
GND_6 GND_7
21 24
C7127 33nF C7045
AVDD BST2_P
22 23
C7128 33nF C7046
GVDD BST2_M
R7040
IC7001 IC7001
PGND
IC7001 IC7001
C7204 C7204
3-12
Copyright © 2022 LG Electronics Inc. All rights reserved.
PVDD
C7204 C7205
330uF /35V
IC7002
1 44
C7039 33nF
BST1_P
VDD
2 43
C7040 33nF
BST1_M
GAIN/SLV
3 42
GND_12
OTW_CLIP
4 41
GND_11
FAULT
5 40
OUT1_P_2
GND_1
6 39
OUT1_P_1
GND_2
TL
1uF 50V 7 38 C7041 1uF 50V
PVDD_6
GND_3
8 37
PVDD_5
IN1_P
1uF 50V 9 36 C7042 1uF 50V
PVDD_4
IN1_M
10 35
OUT1_M
RESET
11 34
GND_10
HEAD
12 33
GND_9
OSCM
13 32
OUT2_P
OSCP
14 31 C7043
1uF 50V 1uF 50V
PVDD_3
FREQ_ADJ
15 30
PVDD_2
IN2_P
C7044
1uF 50V 16 29 1uF 50V
PVDD_1
IN2_M
17 28
OUT2_M_2
CMUTE
18 27
OUT2_M_1
SL
GND_4
19 26
GND_5
GND_8
20 25
GND_6 GND_7
21 24
33nF C7047 33nF
AVDD BST2_P
22 23
33nF C7048 33nF
GVDD BST2_M
R7041 330K(M)
330K(M)
IC7002 IC7002
C7206
330uF/35V
PGND
IC7002 IC7002
C7205 C7205
Only for training and service purposes.
PGND