LG 42LN5700 Service Manual page 71

Standard Repair Process
Error
LCD TV
symptom
→ abnormal audio/discontinuation/noise is same after "Check input signal" compared to No audio
Check input
signal
Signal
-RF
normal?
-External Input
signal
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Only for training and service purposes
C. Audio error
Wrecked audio/ discontinuation/noise
Y
N
(When RF signal is not
received)
Request repair to external
cable/ANT provider
(In case of External
Input signal error)
Check and fix
external device
Established
Revised date
Wrecked audio/
Check and replace
Discontinuation/
speaker and
Noise for
connector
all audio
Wrecked audio/
Discontinuation/
Replace Main B/D
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
11 / 97
2012. 12 .21
date
☞A25
Check audio
B+ Voltage (24V)
Y
Normal
voltage?
N
Replace Power B/D
Replace Main B/D
N
Normal
audio?
Y
Check and fix external device
9/13
End
LGE Internal Use Only