LG 42LH3000 / 42LH3010 / 42LH3020 / 42LH3040 (CHASSIS:LD91A) Service Manual ▷ View online
B. Power error
No power
Power LED
On?
Y
N
DC Power on
by pressing Power Key
On Remote control
by pressing Power Key
On Remote control
Y
N
Normal
operation?
Check Power
On ‘”High”
On ‘”High”
Check Power cord
was inserted properly
Check
Power LED
Power LED
Replace
Power
Power
B/D
Measure voltage of each output of Power B/D
N
Y
Normal
voltage?
Replace Main B/D
N
Y
OK?
Replace Main B/D
N
Y
Normal?
Check ST-BY 5V
Replace Power B/D
N
Y
Normal
voltage?
Replace Power
B/D
B/D
Y
Standard Repair Process
Established
date
Revised date
2008. 3 .05
6/13
LCD TV
Error
symptom
’
09 years new model apply
mechanical power switch
to reduce power consumption in stand-by status.
If mechanical power switch off
Doesn’t turn on by remote control
Doesn’t appear LED light
Please refer to the A21 Page
6
. Stand-By: Red
. Operating: Green
Check & Repair
Mechanical Power switch
on Local control of TV
Close
B. Power error
Off when on, off while viewing, power auto on/off
Error?
N
Y
Check Power Off
Mode
Mode
Fix A/C code & Outlet
and describe 3 wave
and describe 3 wave
length
Check A/C code
Check for 3 wave length
Check outlet
Replace Main B/D
CPU
Abnormal
(If Power Off mode
is not displayed)
Check Power B/D
voltage
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
Caution
Check and fix exterior
of Power B/D Part
of Power B/D Part
Established
date
Revised date
2008. 3 .05
7/13
LCD TV
Error
symptom
Standard Repair Process
7
Status
Power off List
Explanation
Normal
"POWEROFF_REMOTEKEY"
Power off by REMOTE CONTROL
"POWEROFF_OFFTIMER"
Power off by OFF TIMER
"POWEROFF_SLEEPTIMER"
Power off by SLEEP TIMER
"POWEROFF_INSTOP"
Power off by INSTOP KEY
"POWEROFF_AUTOOFF"
Power off by AUTO OFF
"POWEROFF_ONTIMER"
Power off by ON TIMER
"POWEROFF_RS232C"
Power off by RS232C
"POWEROFF_RESREC"
Power off by Reservated Record
"POWEROFF_RECEND"
Power off by End of Recording
"POWEROFF_SWDOWN"
Power off by S/W Download
"POWEROFF_UNKNOWN"
Power off by unknown status except listed case
Abnormal
"POWEROFF_ABNORMAL1"
Power off by abnormal status except CPU trouble
"POWEROFF_CPUABNORMAL"
Power off by CPU Abnormal
* Please refer to the all cases which
can be displayed on power off mode.
can be displayed on power off mode.
Abnormal
1
No audio
Screen normal
Check user
menu >
Speaker off
menu >
Speaker off
Off
N
Y
Cancel OFF and describe
Check audio B+
20V or 24V of
Power Board
20V or 24V of
Power Board
Normal
voltage
voltage
Y
N
Replace Power Board and repair parts
Check
Speaker
disconnection
Speaker
disconnection
N
Y
Replace Speaker
Replace MAIN Board
End
C. Audio error
No audio/ Normal video
Disconnection
Established
date
Revised date
2008. 3 .05
8/13
LCD TV
Error
symptom
Standard Repair Process
8
Wrecked 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
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
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
-RF
-External Input
signal
Signal
normal?
(When RF signal is not
received)
Request repair to external
cable/ANT provider
received)
Request repair to external
cable/ANT provider
Y
Check audio
B+ Voltage (20V or 24V)
B+ Voltage (20V or 24V)
Replace Main B/D
(In case of
External Input
signal error)
Check and fix
external device
External Input
signal error)
Check and fix
external device
Replace Main B/D
N
End
Established
date
Revised date
2008. 3 .05
9/13
LCD TV
Error
symptom
Standard Repair Process
9
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