LG SL8YG Service Manual page 35

NO BOOTING WHEN YOU TURN THE UNIT ON, NO MESSAGE OR
"HELLO" ON FRONT PANEL
When you turn on your set, no message on the front panel, and LED doesn't work.
1-4. LCD System power VCC_5 V, 3.3 VA (No 5 V, 3.3 VA)
1-4-1. Solution
Replace MAIN / FRINT AMP board.
1-4-2. How to troubleshoot (Countermeasure)
1) Please check 3.3 VA of IC312 pin2.
2) If PMIC_4.1 V is abnormal, replace MAIN board.
3) If PMCI_4.1 V is OK, replace FRONT board.
1-4-3. Service hint (Any picture / Remark)
 
R 3 9 3
R 3 9 4
C 3 0 9
I C 3 1 2
R 3 6 0
C 3 0 4
R 3 3 6
C 3 4 4
C 3 9 8
C 3 4 9
B 6
C 3 7 5
C 3 7 6
F B 3 1 5
ONE POINT REPAIR GUIDE
VCC_5V
220 (M)
R1B7
FB104
PZ1608U221-1R4TF
R1B8 220 (M)
C163
C162
C165
10uF
100nF
10nF
/10V(M)
DGND
LCD_STB
LCD_RST
LCD_CD
LCD_CLK
LCD_DAT
C
Q102
LCD_BL B
KRC103S
E
DGND
D 3 0 4
C 3 0 5
I C 5 0 4
C 3 0 6
C 3 0 7
F B 3 2 3  
C 3 4 8
L 3 1 1
C 3 1 0
C N 1 0 3
 
C 1 6 8
Q 1 0 2
CN103 CN103
< MAIN board top view >
Front_LCD
EAG30500902
  04-6214-014-000-800
0.5MM, STRAIGHT
3.3VA
CN103
TP158
1
TP159
2
R1C6 0 NC TP160
3
R1C7 0 NC TP161
4
R1C8 0 NC TP162
5
R1C9 0 NC TP163
6
R1D0 0 NC TP164
7
TP165
8
TP166
9
TP167
10
TP169
11
C166 C168
2.2uF 2.2uF
TP168
12
/10V(X5R) /10V(X5R)
TP170
13
NC
C1A1
TP171
14
C167 0.33uF
R1D3 10M
DGND
C 5 A 1
C 5 C 3 C 5 A 8 C 5 9 9 C 5 C 1
C L 5 0 1
C 3 4 7
I C 3 1 5
C 3 M 4
R 3 A 4
3-8
Copyright © 2019 LG Electronics Inc. All rights reserved.
LED+(A)
LED-(K)
CSB
RSTB
CD
SCK
SDA
VDD
VSS
VB0-
VB1-
VB1+
VB0+
VLCD
T P 4 1 4
R 4 8 1
R 4 8 4
R 4 8 0
R 4 7 9
R 4 8 3 R 4 7 8
R 3 E 7
R 4 7 7
R 4 8 2 R 4 6 9
T P 4 1 1
F B 3 2 1
F B 4 1 4
C 3 F 3
C 1 5 1
C 2 P 3
C N 2 0 3
Only for training and service purposes.
C 3 F
I C 4 0 5 T P 4 1 2
C 4 7 1
R 4 6
Q 4 0 1
R 2 5 4
C 2 6 5 C 2 6 2