LG 28LM4 0B-PU Series Service Manual page 32

Standard Repair Process
Error
symptom
→ abnormal audio/discontinuation/noise is same after "Check input signal" compared to No audio
Check input
signal
Signal
-RF
normal?
-External Input
signal signal
N N
C. Audio error
Wrecked audio/ discontinuation/noise
Y
(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
date
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/
Replace Power B/D
Noise only
for Analog
Wrecked audio/
Discontinuation/
Noise only
for External Input for External Input
Connect and check
other external
device
- 32 -
9/13
A20+A18
Check audio Check audio
B+ Voltage (12.5V)
Y
Normal
voltage? voltage?
N
End
Replace Main B/D
N
Normal
audio?
Y
Check and fix external device
2019