LG 37LH50YD (CHASSIS:LB91B) Service Manual ▷ View online
LCD TV Repair Process Index
- Trouble shooting by input block (Component level check)
No.
Symptom (L)
Input Block
Page
Remark
1
Power Problem
Power-up Boot fail
2
Video Problem
No OSD
3
Digital TV
4
Analog TV
5
AV (Scart / CVBS/ S-Video)
6
Component
7
RGB(D-SUB)
8
HDMI
9
Audio Problem
All Input
10
Digital TV
11
Analog TV
12
AV / Component / RGB, HDMI-PC/ HDMI-DTV
13
AV Audio out / No Audio (Headphone &
SPDIF)
SPDIF)
14
USB / Remocon Problem
USB no connect / Remocon
15
Intelligent Sensor
Intelligent Sensor
P800 Pin #7~#10
Voltage Level = 5V ?
P800 Pin #2
Voltage level = 5V ?
Check Power connector
OK ?
Replace Power Board
YES
NO
YES
P800 Pin #13, 14 = 12V
P800 Pin #17, 18 = 24V ?
NO
Replace Power Board
YES
NO
Replace MAIN B’D Q801
MAIN B’D L815 = 3.3V ?
Replace MAIN B’D IC804
YES
NO
MAIN B’D L816 = 1.26V ?
Replace MAIN B’D IC805
YES
NO
MAIN B’D L809 = 1.8V ?
Replace MAIN B’D IC807
YES
NO
Check MAIN B’D X100 Clock
12MHz
Replace MAIN B’D IC100
YES
NO
Replace MAIN B’D IC102
NAND FLASH
YES
Replace MAIN B’D IC103
Serial Flash
NO
Replace MAIN B’D
IC300, IC301 DDR2 Memory
NO
Replace MAIN B’D IC100
NO
Making
Revision
2009. 2 . 1
1/25
LCD TV
Symptom
Power-Up Boot Fail
P800 Pin #20
Voltage level = 2V ↑
Check Power connector
OK ?
Replace Power Board
YES
NO
YES
NO
YES
Replace MAIN B’D Q802
MAIN B’D L810 = 12V ?
Replace MAIN B’D Q805
NO
Replace Main Board
YES
P800 Pin #13, 14 = 12V
P800 Pin #17, 18 = 24V ?
Check LVDS Cable
OK ?
YES
Replace LVDS Cable
NO
Making
Revision
2009. 2 . 1
LCD TV
Symptom
No OSD
2/25
Check RF Cable
MAIN B’D L1111 = 5V ?
YES
MAIN B’D L1112 = 3.3V ?
NO
Replace MAIN B’D IC1103
YES
NO
Replace MAIN B’D IC808
MAIN B’D L1113 = 1.8V ?
Replace MAIN B’D IC1105
YES
NO
YES
MAIN B’D X1101 Clock ?
NO
Replace MAIN B’D X1101
Making
Revision
2009. 2 . 1
LCD TV
Symptom
Digital TV Video Problem
3/25
Click on the first or last page to see other 37LH50YD (CHASSIS:LB91B) service manuals if exist.