One Point Repair Guide - LG SL8YG Service Manual

1. 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.
1-1. IC604 System 12 VA (No 12 VA)
1-1-1. Solution
Replace AMP board.
1-1-2. How to troubleshoot (Countermeasure)
1) Please check 25 VA of IC604 pin2(VIN).
2) If 25 VA is abnormal, please check Adapter.
3) If 25 VA is OK, but 12 VA is abnormal pin3 of IC604(VOUT), replace MAIN board.
1-1-3. Service hint (Any picture / Remark)
25VA
FB611
EAM38769505
UBW2012-121F
DGND
C A 6 8 0
A R 6 0 8
F B 6 0 8
6 0 4 C A 6 4 1
P - C L K
P - D A T
I C 6 1 3
0 R A 6 7 8
R A 6 2 0
C A 6 0 2
R A 6 1 9
C A 6 0 4
7 Y Y
7 Y G

ONE POINT REPAIR GUIDE

[25VA TO 12VA]
RA664
8
7
CA667 RA657
6
33pF 51K
(1%)
5
RA665
100K
RA660
VOUT = 0.792x(47K/3.3K+1)= 12.072V
DGND
C A 6 8 1
S L 8 A M P F R 4 - 4 L 1 . 4 T
E A X 6 8 4 2 3 0 0 1 V e r 1 . 5
1
P C B S I Z E : 2 3 3 X 9 9
2 0 1 9 . 0 1 . 0 8
< AMP board top view >
IC604
100K
  1
FB
PG
2
DGND
VCC
IN
3
L611
EN/SYNC
SW
4
BST
GND
DGND
22 CA656
100nF
L 6 1 1
 
L611 L611
I C 6 0 4
R A 6 5 7
C A 6 6 7
 
IC604 IC604
3-5
Copyright © 2019 LG Electronics Inc. All rights reserved.
RA667 0
PWR_GD
RA674
150K
 
10UH
RA671
DV delete
DGND
R A 6 7 9
F 6 0 1
F 6 0 2
F B 6 1 1
R A 6 5 8
R A 6 6 5
Only for training and service purposes.
12VA
R 7 5 7
R 7 5 3