LG 42LA790V / 42LA790W (CHASSIS:LD34D) Service Manual ▷ View online
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Established
date
Standard Repair Process Detail Technical Manual
Revised
date
A1
Error
symptom
Content
Check LCD back light with naked eye
A. Video
error_No
video/Normal audio
After turning on the power and disassembling the case, check with the naked
eye, whether you can see light from 4 locations.
<XXLA79XX>
LCD TV
2012. 12 .06
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Entry method
1. Press the ADJ button on the remote controller for adjustment.
2. Enter into White Balance of item 6.
3. After recording the R, G, B (GAIN, Cut) value of Color Temp (Cool/Medium/Warm), re-
enter the value after replacing the MAIN BOARD.
Standard Repair Process Detail Technical Manual
Check White Balance value
A. Video error_No video/Normal audio
<ALL MODELS>
A4
Established
date
Revised
date
Error
symptom
Content
LCD TV
Entry method
1. Press the ADJ button on the remote controller for adjustment.
2. Enter into White Balance of item 10.
3. After recording the R, G, B (GAIN, Cut) value of Color Temp (Cool/Medium/Warm), re-
enter the value after replacing the MAIN BOARD.
2012. 12 .06
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Standard Repair Process Detail Technical Manual
Power Board voltage measuring method
A. Video error_No video/ Audio
A5
Established
date
Revised
date
Error
symptom
Content
LCD TV
Check the DC 24V, 12V, 3.5V.
24 Pin
(Power Board ↔ Main Board)
SMAW200-H24S
1
Power on
2
Inverter On/off
3
3.5V
4
PWM Dim #1
5
3.5V
6
PWM Dim #2
7
GND
8
GND
9
24V
10
24V
11
GND
12
GND
13
12V
14
12V
15
12V
16
24V
17
GND
18
GND
19
GND
20
GND
21
GND
22
L/DIMO_VS
23
L/DIM0_MOSI
24
L/DIM0_SCLK
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MENU support signal test
select channel
When the signal is strong, use the
attenuator (-10dB, -15dB, -20dB etc.)
Standard Repair Process Detail Technical Manual
TUNER input signal strength checking method
A. Video error_Video error, video lag/stop
<ALL MODELS>
A6
Established
date
Revised
date
Error
symptom
Content
LCD TV
2012. 12 .06
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