LG 28LM4 0B-PU Series, Service Manual, Page: 32 / 69

C. Audio error
Wrecked audio/ discontinuation/noise
Established
date
Revised date
9/13
Error
symptom
Standard Repair Process
→ abnormal audio/discontinuation/noise is same after “Check input signal” compared to No audio
Check and replace
Check audio
ත
A20+A18
Wrecked audio/
speaker and
connector
Y
Normal
voltage?
Check input
signal
-RF
-External Input
signal
Signal
normal?
Y
Check audio
B+ Voltage (12.5V)
N
Discontinuation/
Noise for
all audio
N
voltage?
signal
Replace Main B/D
N
Wrecked audio/
Discontinuation/
Noise only
for D-TV
Replace Power B/D
(When RF signal is not
received)
Request repair to external
cable/ANT provider
Replace Main B/D
End
Wrecked audio/
Discontinuation/
Noise only
for Analog
N
(In case of
External Input
signal error)
Check and fix
external device
Wrecked audio/
Discontinuation/
Noise only
for External Input
Connect and check
other external
device
Normal
audio?
for External Input
Y
Check and fix external device
- 32 -
2019