LG 42LN5700 (CHASSIS:LJ33B) Service Manual ▷ View online
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B. Power error
Off when on, off while viewing, power auto on/off
※
Caution
Check and fix exterior
of Power B/D Part
Established
date
Revised date
7/13
LCD TV
Error
symptom
* Please refer to the all cases which can be displayed on power off mode.
Click the below Hyper_link
Error?
N
Y
Check Power Off
Mode
Fix A/C cord & Outlet
and check each 3
phase out
Check A/C cord
Check for all 3- phase
power out
Check outlet
Replace Main B/D
CPU
Abnormal
(If Power Off mode is
not displayed)
Check Power B/D
voltage
Y
N
Replace Main B/D
Normal
voltage?
Replace Power B/D
Replace Power B/D
N
Y
Normal?
End
☞
A22
☞
A19
Abnormal
1
2012. 12 .21
Standard Repair Process
10 / 97
No audio
Screen normal
Check user
menu >
Sound Out
TV
Speaker?
Y
N
Change the TV Speaker
Check audio B+ 24V
of Power Board
Normal
voltage
Y
N
Replace Power Board and repair parts
Check Speaker
disconnection
N
Y
Replace Speaker / Cable
Replace MAIN Board
End
C. Audio error
No audio/ Normal video
☞
A24
☞
A25
Disconnection
Established
date
Revised date
8/13
LCD TV
Error
symptom
2012. 12 .21
Standard Repair Process
11 / 97
→
abnormal audio/discontinuation/noise is same after “Check input signal” compared to No audio
C. Audio error
Wrecked audio/ discontinuation/noise
Wrecked audio/
Discontinuation/
Noise for
all audio
Check and replace
speaker and
connector
Wrecked audio/
Discontinuation/
Noise only
for D-TV
Wrecked audio/
Discontinuation/
Noise only
for Analog
Wrecked audio/
Discontinuation/
Noise only
for External Input
Connect and check
other external device
N
Y
Normal
audio?
Check and fix external device
Replace Power B/D
N
Y
Normal
voltage?
Check input
signal
-RF
-External Input
signal
Signal
normal?
(When RF signal is not
received)
Request repair to external
cable/ANT provider
Y
Check audio
B+ Voltage (24V)
Replace Main B/D
(In case of External
Input signal error)
Check and fix
external device
Replace Main B/D
N
End
Established
date
Revised date
9/13
LCD TV
Error
symptom
☞
A25
2012. 12 .21
Standard Repair Process
12 / 97
D. General Function Problem
Remote control & Local switch checking
Y
N
1. Remote control(R/C) 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+ 3.5V
On Main B/D
☞
A27
Normal
Voltage?
Close
N
N
Check 3.5v on Power B/D
Replace Power B/D or
Replace Main B/D
(Power B/D don’t have problem)
☞
A4
Check IR
Output signal
Normal
Signal?
N
Y
Repair/Replace
IR B/D
N
☞
A27
Replace
Main B/D
Y
☞
A27
Established
date
Revised date
10/13
LCD TV
Error
symptom
2012. 12 .21
Standard Repair Process
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