LG 42LN655V (CHASSIS:LD33B) Service Manual ▷ View online
20 / 88
Normal
voltage?
Check various voltages
of Power Board
( 3.5V,12V,20V or 24V…)
No Video/
No audio
Check and
replace
MAIN B/D
Y
Replace Power
Board and repair
parts
N
End
Standard Repair Process
A. Video error
No video/ No audio
☞A4
Established
date
Revised date
LCD TV
Error
symptom
2012. 12 .06
21 / 88
A. Picture Problem
Picture broken/ Freezing
Y
N
☞ A6
N
Check RF Signal level
Normal
Signal?
Check RF Cable
Connection
1. Reconnection
2. Install Booster
Check
S/W Version
Use Signal Test
Check Signal status
S/W Upgrade
Check whether other equipments have problem or not.
(By connecting RF Cable at other equipment)
→ DVD Player ,Set-Top-Box, Different maker TV etc`
SVC
Bulletin?
Replace
Main B/D
Check
Tuner soldering
Normal
Picture?
Y
N
Y
Close
Normal
Picture?
Y
Close
. By using Digital signal level meter
. By using Diagnostics menu on OSD
( Menu→ Set up→ Support → Signal Test )
- Signal strength (Normal : over 50%)
- Signal Quality (Normal: over 50%)
Normal
Picture?
Y
Contact with signal distributor
or broadcaster (Cable or Air)
N
N
Normal
Picture?
Y
Close
N
☞ A7
Standard Repair Process
Established
date
Revised date
LCD TV
Error
symptom
2012. 12 .06
22 / 88
A. Picture Problem (DVB-S/S2)
Tuning fail, Picture broken/ Freezing
Y
N
☞ A6
Check RF Signal level
Normal
Signal?
Check
S/W Version
S/W Upgrade
SVC
Bulletin?
Normal
Picture?
Y
N
Y
Close
Check RF signal cable (DVB satellite signal or not)
Check whether other equipments have problem or not.
(By connecting RF Cable at other equipment)
→ Set-Top-Box, Different maker TV etc
Y
Change satellite setting
(match with installed ANT)
N
Normal
Picture?
Y
Close
N
☞ A7
Standard Repair Process
Established
date
Revised date
LCD TV
Error
symptom
Check satellite setting.
- Check LNB frequency.
- Check satellite
- Check Satellite connection
(DiSEqC, motor, etc…)
Normal
setting?
Contact with
signal distributor
or broadcaster
(Cable or Air)
Close
N
Check
Tuner soldering
Replace
Main B/D
2012. 12 .06
23 / 88
Color
error?
Y
N
※ Check and
replace Link
Cable
(LVDS) and
contact
condition
replace Link
Cable
(LVDS) and
contact
condition
Y
N
Replace Main B/D
Color
error?
Check error color
input mode
Check color by input
-External Input
-COMPONENT
-RGB
-HDMI/DVI
Y
External device
/Cable
normal
External Input/
Component
error
Check
external
device and
cable
Y
External device
/Cable
normal
RGB/
HDMI/DVI
error
Check external
device and
cable
Replace Main B/D
Replace Main B/D
N
N
A. Video error
Color error
☞A8
N
Y
End
Replace module
Request repair
for external
device/cable
Color
error?
Check Test pattern
☞A12
☞ A10/ A11
Standard Repair Process
Established
date
Revised date
LCD TV
Error
symptom
2012. 12 .06
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