LG 42LH20FD (CHASSIS:LT91A) Service Manual ▷ View online
D. General Function Problem
Remote control & Local switch checking
Y
N
1. Remote control(R/C) operating error
Move
Power problem
Section
2. Local(Mechanical) switch operating error
Check R/C itself
Operation
Normal
operating?
Normal
operating?
Y
Close
Replace R/C
If R/C operate,
Explain the customer
cause is interference
from light in room.
Check R/C Operating
When turn off light
in room
Check & Replace
Baterry of R/C
Check & Repair
Cable connection
Connector solder
Normal
operating?
Check B+ 5V
On Main B/D
Normal
Voltage?
Close
N
N
Check 5v on Power B/D
Replace Power B/D or
Replace Main B/D
(Power B/D don’t have problem)
Check IR
Output signal
Normal
Signal?
N
Y
Repair/Replace
IR B/D
N
Replace
Main B/D
Y
Y
N
Check R/C
Operation
Normal
operating?
Y
Check & Repair
Cable connection
Connector solder
Normal
operating?
Close
N
Check & Replace
Assembly status
(Key PCB + tool )
Check Key
Output signal
Y
Normal
operating?
Close
N
Normal
Signal?
Repair/Replace
Local switch B/D
N
Replace
Main B/D
Y
Standard Repair Process
Established
date
Electronics 6-3
Revised date
2008. 3 .05
10/13
LCD TV
Error
symptom
10
Check technical
information
- Fix information
- S/W Version
information
- Fix information
- S/W Version
N
Y
Technical
information?
Check
input
signal
input
signal
Signal
input?
input?
Y
N
External Input and
Component
Recognition error
Check and fix
external device/cable
external device/cable
RGB,HDMI/
DVI, Optical
Recognition error
Replace Main B/D
Replace Main B/D
Fix in
accordance
with technical
information
D. Function error
External device recognition error
Established
date
Electronics 6-3
Revised date
2008. 3 .05
11/13
LCD TV
Error
symptom
Standard Repair Process
11
Check
location of
noise
location of
noise
Identify
nose
type
nose
type
Circuit
noise
Replace inverter
Replace LIPS B/D
Mechanical
noise
Check location
of noise
of noise
OR
※ When the nose is severe, replace the module
(For models with fix information, upgrade the
S/W or provide the description)
(For models with fix information, upgrade the
S/W or provide the description)
OR
※ If there is a “Tak Tak” noise from the
cabinet, refer to the KMS fix information and
then proceed as shown in the solution manual
(For models without any fix information,
provide the description)
cabinet, refer to the KMS fix information and
then proceed as shown in the solution manual
(For models without any fix information,
provide the description)
OR
※ Mechanical noise is a natural
phenomenon, and apply the 1st level
description. When the customer does not
agree, apply the process by stage.
※ Describe the basis of the description
in “Part related to nose” in the Owner’s
Manual.
phenomenon, and apply the 1st level
description. When the customer does not
agree, apply the process by stage.
※ Describe the basis of the description
in “Part related to nose” in the Owner’s
Manual.
E. Noise
Circuit noise, mechanical noise
<With Inverter Module>
<Without Inverter Module>
Established
date
Electronics 6-3
Revised date
2008. 3 .05
12/13
LCD TV
Error
symptom
Standard Repair Process
12
Replace module
Zoom part with
exterior damage
exterior damage
Module
damage
Cabinet
damage
Replace cabinet
Replace remote controller
Remote
controller
damage
Stand
dent
Replace stand
F. Exterior defect
Exterior defect
Adjust VCOM
Established
date
Electronics 6-3
Revised date
2008. 3 .05
13/13
LCD TV
Error
symptom
Standard Repair Process
13
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