LG 26LH1DCX-UX / 26LH1DC3-UA / 26LH1DC4-UB / 26LH1DC5-UC Service Manual ▷ View online
-21-
NO KEY
FUNTION
REAMARK
To turn the TV on or off.
To turn the TV on automatically if the power is supplied to the TV. (Use the
POWER key to deactivate) : It should be deactivated when delivered.
To turn the TV on automatically if the power is supplied to the TV. (Use the
POWER key to deactivate) : It should be deactivated when delivered.
To activate the mute function.
N/A
N/A
To select size of the main screen. (Normal, Spectacle, Wide or Zoom)
Switch to closed caption broadcasting.
N/A
To select an external input for the TV screen.
N/A
N/A
To enter adjustment mode when manufacturing the TV sets.
W/B adjustment. (automatic)
N/A
N/A
To select size of the main screen. (Normal, Spectacle, Wide or Zoom)
Switch to closed caption broadcasting.
N/A
To select an external input for the TV screen.
N/A
N/A
To enter adjustment mode when manufacturing the TV sets.
W/B adjustment. (automatic)
To enter into the adjustment mode.
To select the multiple sound mode. (Mono, Stereo or Foreign language)
To release the adjustment mode.
To easily adjust the screen according to surrounding brightness.
To easily adjust sound according to the program type.
To check component input.
To check the front AV.
To move channel up/down or to select a function displayed on the screen.
To adjust the volume or accurately control a specific function.
To set a specific function or complete setting.
N/A
N/A
N/A
N/A
N/A
To select the functions such as picture, sound, channel, setup, caption.
To set the delivery condition status after manufacturing the TV set.
To halt the main screen in the nomal mode.
N/A
N/A
N/A
N/A
N/A
N/A
N/A
To manually select the channel.
To select the multiple sound mode. (Mono, Stereo or Foreign language)
To release the adjustment mode.
To easily adjust the screen according to surrounding brightness.
To easily adjust sound according to the program type.
To check component input.
To check the front AV.
To move channel up/down or to select a function displayed on the screen.
To adjust the volume or accurately control a specific function.
To set a specific function or complete setting.
N/A
N/A
N/A
N/A
N/A
To select the functions such as picture, sound, channel, setup, caption.
To set the delivery condition status after manufacturing the TV set.
To halt the main screen in the nomal mode.
N/A
N/A
N/A
N/A
N/A
N/A
N/A
To manually select the channel.
SVC REMOCON
POWER
POWER ON
MUTE
P-CHECK
S-CHECK
ARC
CAPTION
TXT
TV/AV
TURBO SOUND
TURBO PICTURE
P-CHECK
S-CHECK
ARC
CAPTION
TXT
TV/AV
TURBO SOUND
TURBO PICTURE
IN-START
ADJ
MPX
EXIT
APC(PSM)
ASC(SSM)
MULTIMIDIA
FRONT-AV
CH
MPX
EXIT
APC(PSM)
ASC(SSM)
MULTIMIDIA
FRONT-AV
CH
±
VOL
±
ENTER
PIP CH-(OP1)
PIP CH+(OP2)
PIP SWAP(OP3)
PIP INPUT(OP4)
EYE
MENU
IN-STOP
STILL
TIME
SIZE
MULTI PIP
POSITION
MODE
PIP
TILT
0~9
PIP CH-(OP1)
PIP CH+(OP2)
PIP SWAP(OP3)
PIP INPUT(OP4)
EYE
MENU
IN-STOP
STILL
TIME
SIZE
MULTI PIP
POSITION
MODE
PIP
TILT
0~9
1
2
3
4
5
6
7
8
9
4
5
6
7
8
9
10
11
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
Shortcut keys
Shortcut keys
Shortcut keys
Shortcut keys
Shortcut keys
Shortcut keys
-22-
TROUBLE SHOOTING GUIDES
Check for problems
in Main Board
Normal operation
Main Board
LED ON?
Power Cable(13 PIN)
Check / Replace
Front Cable(7 PIN)
Check / Replace
SMPS
Check / Replace
Main Board
Replace
PC Serial port
Check the setting
Serial Cable
Check / Replace
LVDS Cable
Check / Replace
Main Board
Replace
External equipment/
Cable Check / Replace
Main Board
Replace
External equipment/
Cable Check / Replace
Main Board
Replace
Speaker Cable
Check / Replace
Check for problems
in audio
MICOM
Check the operation
Main Board
Replace
Is it communicating
with the Service Port?
Is the screen
color normal?
Is the color normal
when PC/HDMI
is selected?
Is the color normal
when External Input/
S-Video/Component
is selected?
Is the left/right audio
output normal?
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
-23-
1. Check if the SMPS power is connected to the Main board and stand-by power connected, and whether green light is on for LED(D101).
If the green light is not on, check the stand-by power(5V).
2. Turn ON the POWER using the remote controller or the front key button.
At this time, check whether the green light is on for LED (D102).
If the green light is not on, measure the next power with DMM.
If the green light is not on, measure the next power with DMM.
- Pin no. 3, 4 and 5 of CN101 (D12V)
- Input/output voltage of IC503 (D12V, D6V)
- Input/output voltage of IC710 (D6V, A5V)
- Input/output voltage of IC503 (D12V, D6V)
- Input/output voltage of IC710 (D6V, A5V)
3. Check whether the LCD panel is operating normally.
If the display is not working normally, check the LVDS cable and take the following actions.
- Check the input/output voltage of IC501. (D12V, D3.3V)
- Check the input/output voltage of IC704. (D3.3V, D2.5V)
- Check the input/output voltage of IC714. (D3.3V, D1.8V)
- Connect the UART Cable to the Service Port and activate the debugger window of the PC.
- Check the input/output voltage of IC704. (D3.3V, D2.5V)
- Check the input/output voltage of IC714. (D3.3V, D1.8V)
- Connect the UART Cable to the Service Port and activate the debugger window of the PC.
After connecting the power to the Main board, check whether the booting flow is normally written in the debugger window of the PC.
(To enable communications with the PC, always use the UART cable checked for normal operation.)
(To enable communications with the PC, always use the UART cable checked for normal operation.)
- If the booting flow is not written at all in the debugger window of the PC, check the power(D3.3V, D2.5V, D1.8V) connected to the main chip(IC401).
And then if there is no problem with the power, check the connection pattern condition of the main chip(IC401) and the Flash memory(IC403),
and check the cold solder or short circuit of each pin of the flash memory.
and check the cold solder or short circuit of each pin of the flash memory.
- If only 1 line of booting flow is written in the debugger window of the PC and nothing after that, check the power(D3.3V, D2.5V, D1.8V) connected
to the main chip(IC401).
And if there is no problem with the power, check the cold solder or short circuit of the array resistance(RA403-RA416) connected to the main chip
and DDR memory(IC402 and IC404).
Check the cold solder or short circuit of each pin of the DDR memory.
And if there is no problem with the power, check the cold solder or short circuit of the array resistance(RA403-RA416) connected to the main chip
and DDR memory(IC402 and IC404).
Check the cold solder or short circuit of each pin of the DDR memory.
- When the booting flow is normally written in the debugger window of the PC but rebooting, check the communications line(SCL1, SDA1) of MICOM
(IC705) and main chip(IC401).
4. Check whether the digital broadcasting is normally received. If it is not normally received, check the following.
- Measure the power of no. 3 pin of TUNER(IC105). (TU5V)
- Measure the power of no. 12 pin of TUNER(IC105). (TU3.3V)
- Measure the power of no. 15 pin of TUNER(IC105). (TU1.8V)
- Check the cold solder and short circuit etc. of the serial resistance(RA101, RA102) and other resistances(R114~R116) of the TS Data line.
- Check the communications line(SCL0, SDA0).
- Measure the power of no. 12 pin of TUNER(IC105). (TU3.3V)
- Measure the power of no. 15 pin of TUNER(IC105). (TU1.8V)
- Check the cold solder and short circuit etc. of the serial resistance(RA101, RA102) and other resistances(R114~R116) of the TS Data line.
- Check the communications line(SCL0, SDA0).
5. If the digital broadcasting is normally received but the analog broadcasting is not received normally, check the no.16 pin of IC706(74VHC4051).
(CVB_5V) For a more detail review, check the signal wave form of Q106, Q101, Q104 etc. with the oscilloscope.
6. Check if the external input of AV1, 2, 3, S-Video etc. If the video does not show well, check whether there is any problem with IC706, which is the analog
video switch.
If a specific external input does not work, check the external input device and check whether there is any problem with the cable.
If not identified simply, check for problems following the signal of “Video/audio signal flow chart”.
If not identified simply, check for problems following the signal of “Video/audio signal flow chart”.
7. Check the external input of Component1 and 2.
If the video of the Component does not work at all, check if there is any problem in IC202, the component video switch and IC201, AD converter.
If a specific external input does not work, check the external input device and check whether there is any problem with the cable.
If not identified simply, check for problems following the signal of “Video/audio signal flow chart”.
If a specific external input does not work, check the external input device and check whether there is any problem with the cable.
If not identified simply, check for problems following the signal of “Video/audio signal flow chart”.
8. Check the PC input and HDMI(DVI) input.
If the PC video does not work, check whether there is any problem with the connection cable.
If the HDMI video does not work or only the video works without any audio, rewrite the EDID data.
If the HDMI video does not work or only the video works without any audio, rewrite the EDID data.
9. Check if the left/right side of the audio working normally.
Check the cold solder and short circuit of IC708(STA323W) when the audio does not work.
For analog broadcasting, check the cold solder and short circuit of IC602(MSP3425) since it goes through this.
For analog broadcasting, check the cold solder and short circuit of IC602(MSP3425) since it goes through this.
-24-
1. No Screen(1)
Symptom
Front LED is on as green color, but no picture.
Check Flow
TROUBLE SHOOTING
Check LVDS Cable?
Is the LVDS cable connected well?
Reset Cable
Replace LVDS Cable
Check Power On signal?
Is the Power On Signal correct?
Check Key Pad/IR Input
Check Power Supply
Is LCD Voltage +24V/+12V
normal?
Check Power Supply
Video Normal on Analog RF?
Check TUNER
Video normal on Video3?
Check HC4051
Video normal on DIGITAL RF?
Check TUNER
Video normal on
AutoCamport/AV2
Check RJP Mode
Check HC4051
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
NO
NO
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