Booting When You Turn The Unit On, No Green Led On Front Panel - LG UBK80 Service Manual

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.
2-2. IC202 System 3.3 VA_Micom (No 3.3 VA)
2-2-1. Solution
Replace MAIN board.
2-2-2. How to troubleshoot (Countermeasure)
1) Please check 12 VA of IC202 pin1 (VIN).
2) If 12 VA is abnormal, please check SMPS.
3) If 12 VA is OK, but 3.3 VA is abnormal pin2 of IC202(VOUT), replace MAIN board.
2-2-3. Service hint (Any picture / Remark)
[12VA TO 3.3VA_MICOM]
C202
10pF
DGND
R202
13K (1%)
39K (1%)
DGND
ONE POINT REPAIR GUIDE
R219
390K
6 F B
E N
5
B S T
4
R220
150K
R225 33
R208
DGND
R216
3.3K (1%)
VOUT = 0.798x((39K+3.3K)/13K+1)= 3.394V
< MAIN board top view >
 
C211
100nF
1
I V N
 
L202
2
S W
4.7UH
3
G N D
DGND
C207 1uF (1)
3-31
Copyright © 2020 LG Electronics Inc. All rights reserved.
12VA
L206
C216 C224
10uF 10uF _NC
/16V /16V
3.3VA_MICOM
DGND
R229
0OHM
C217
C225 C231
C2B2
10uF 10uF 10uF
100nF
/16V /16V /16V
DGND
 
 
IC202 IC202
Only for training and service purposes.