3-34
Copyright © 2020 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
< MAIN board top view >
C251
22pF
F
n
0
0
1
8
4
2
C
R254
51K (1%)
L210
DGND
DGND
DGND
R255
4.7K
R256
80.6K (1%)
DGND
DGND
12VA
1.0V_Core
C243
22nF
R248
100K
C237
22uF
/16V
C238
22uF
/16V
C263
22uF
/16V
C269
22uF
/16V
C270
22uF
/16V
C271
22uF
/16V
C241
100nF
PWR_CTL3
R253
110K (1%)
C2B6
100nF
R252
100
C239
0.47uF
C2B9
22uF
/16V
C247
82nF
L214
1.5uH
IC205
1
BST
2
SW
3
NC
4
NC
5
EN/SYNC
6
NC
7
PG
8
PGND
9
VIN
10
VOUT
11
FB
12
SS
13
VCC
14
AGND
[12VA TO 1.0V_Core]
IC205
IC205
IC205
IC205
ONE POINT REPAIR GUIDE
NO BOOTING WHEN YOU TURN THE UNIT ON, NO GREEN LED ON
FRONT PANEL
When you turn on your set, Green LED doesn’t work, it will not boot-up.
2-5. IC205 System 1.0 V (No 1.0 V)
2-5-1. Solution
Replace MAIN board.
2-5-2. How to troubleshoot (Countermeasure)
1) Please check 12 VA of IC205 pin9 (VIN).
2) If 12 VA is abnormal, please check SMPS.
3) If 12 VA is OK, but 1.0 V is abnormal pin2 of IC205(VOUT), replace MAIN board.
2-5-3. Service hint (Any picture / Remark)