Follow these safety, servicing and ESD precautions to prevent damage and to protect against potential hazards such as
electrical shock.
1-1-1. Warnings
1.
For continued safety, do not attempt to modify the circuit board.
2.
Disconnect the AC power and DC power jack before servicing.
1-1-2. Servicing the LCD TV
1.
When servicing the LCD TV, Disconnect the AC line cord from the AC outlet.
2.
It is essential that service technicians have an accurate voltage meter available at all times. Check the calibration of
this meter periodically.
1-1-3. Fire and Shock Hazard
Before returning the LCD TV to the user, perform the following safety checks:
1.
Inspect each lead dress to make certain that the leads are not pinched or that hardware is not lodged between the
chassis and other metal parts in the LCD TV.
2.
Inspect all protective devices such as nonmetallic control knobs, insulating materials, cabinet backs, adjustment and
compartment covers or shields, isolation resistorcapacitor networks, mechanical insulators, etc.
3.
Leakage Current Hot Check (Figure 1-1):
WARNING : Do not use an isolation transformer during this test.
Use a leakage current tester or a metering system that complies with American National Standards Institute (ANSI
C101.1, Leakage Current for Appliances), and Underwriters Laboratories (UL Publication UL1410, 59.7).
(READING SHOULD)
NOT BE ABOVE 0.5mA
DEVICE
UNDER
TEST
TEST ALL
EXPOSED METAL
SURFACES
2-WIRE CORD
*ALSO TEST WITH
PLUG REVERSED
(USING AC ADAPTER
PLUG AS REQUIRED)
4.
With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. With the unit’s AC switch
LEAKAGE
CURRENT
TESTER
EARTH
GROUND
Figure 1-1. Leakage Current Test Circuit
rst in the ON position and then OFF, measure the current between a known earth ground (metal water pipe, conduit,
etc.) and all exposed metal parts, including: metal cabinets, screwheads and control shafts.
The current measured should not exceed 0.5 milliamp.
Reverse the power-plug prongs in the AC outlet and repeat the test.
1-1-4. Product Safety Notices
Some electrical and mechanical parts have special safetyrelated characteristics which are often not evident from visual
inspection. The protection they give may not be obtained by replacing them with components rated for higher voltage,
wattage, etc. Parts that have special safety characteristics are identied by on schematics and parts lists. A substitute
replacement that does not have the same safety characteristics as the recommended replacement part might create
shock, re and/or other hazards. Product safety is under review continuously and new instructions are issued whenever
appropriate.
1-1
1-2
1. Precautions
1-2. Servicing Precautions
WARNING: An electrolytic capacitor installed with the wrong polarity might explode.
Caution: Before servicing units covered by this service manual, read and follow the Safety Precautions section of
this manual.
Note:
1-2-1 General Servicing Precautions
1.
Always unplug the unit’s AC power cord from the AC power source and disconnect the DC Power Jack before
attempting to:
(a) remove or reinstall any component or assembly, (b) disconnect PCB plugs or connectors, (c) connect a test
component in parallel with an electrolytic capacitor.
2.
Some components are raised above the printed circuit board for safety. An insulation tube or tape is sometimes
used. The internal wiring is sometimes clamped to prevent contact with thermally hot components. Reinstall all such
elements to their original position.
3.
After servicing, always check that the screws, components and wiring have been correctly reinstalled. Make sure that
the area around the serviced part has not been damaged.
4.
Check the insulation between the blades of the AC plug and accessible conductive parts (examples: metal panels,
input terminals and earphone jacks).
5.
Insulation Checking Procedure: Disconnect the power cord from the AC source and turn the power switch ON.
Connect an insulation resistance meter (500 V) to theblades of the AC plug.
The insulation resistance between each blade of the AC plug and accessible conductive parts (see above) should be
greater than 1 megohm.
6.
Always connect a test instrument’s ground lead to the instrument chassis ground before connecting the positive lead;
always remove the instrument’s ground lead last.
If unforeseen circumstances create conict between the following servicing precautions and any of the
safety precautions, always follow the safety precautions.
Some semiconductor (solid state) devices can be easily damaged by static electricity. Such components are commonly
called Electrostatically Sensitive Devices (ESD). Examples of typical ESD are integrated circuits and some eld-effect
transistors. The following techniques will reduce the incidence of component damage caused by static electricity.
1.
Immediately before handling any semiconductor components or assemblies, drain the electrostatic charge from your
body by touching a known earth ground. Alternatively, wear a discharging wrist-strap device. To avoid a shock hazard,
be sure to remove the wrist strap before applying power to the LCD TV.
2.
After removing an ESD-equipped assembly, place it on a conductive surface such as aluminum foil to prevent
accumulation of an electrostatic charge.
3.
Do not use freon-propelled chemicals. These can generate electrical charges sufcient to damage ESDs.
4.
Use only a grounded-tip soldering iron to solder or desolder ESDs.
5.
Use only an anti-static solder removal device. Some solder removal devices not classied as “anti-static” can generate
electrical charges sufcient to damage ESDs.
6.
Do not remove a replacement ESD from its protective package until you are ready to install it. Most replacement ESDs
are packaged with leads that are electrically shorted together by conductive foam, aluminum foil or other conductive
materials.
7.
Immediately before removing the protective material from the leads of a replacement ESD, touch the protective
material to the chassis or circuit assembly into which the device will be installed.
Caution: Be sure no power is applied to the chassis or circuit and observe all other safety precautions.
8.
Minimize body motions when handling unpackaged replacement ESDs. Motions such as brushing clothes together,
or lifting your foot from a carpeted oor can generate enough static electricity to damage an ESD.
1. Precautions
1-4. Installation Precautions
For safety reasons, more than two people are required for carrying the product.
1.
Keep the power cord away from any heat emitting devices, as a melted covering may cause re or electric shock.
2.
Do not place the product in areas with poor ventilation such as a bookshelf or closet. The increased internal
3.
temperature may cause re.
Bend the external antenna cable when connecting it to the product. This is a measure to protect it from being exposed
4.
to moisture. Otherwise, it may cause a re or electric shock.
Make sure to turn the power off and unplug the power cord from the outlet before repositioning the product. Also check
5.
the antenna cable or the external connectors if they are fully unplugged. Damage to the cord may cause re or electric
shock.
Keep the antenna far away from any high-voltage cables and install it rmly. Contact with the highvoltage cable or the
6.
antenna falling over may cause re or electric shock.
When installing the product, leave enough space (10cm) between the product and the wall for ventilation purposes.
7.
A rise in temperature within the product may cause re.
This section of the service manual describes the disassembly and reassembly procedures for the LN40A650A1F LCD TV.
WARNING: This monitor contains electrostatically sensitive devices. Use caution when handling these components.
3-1. Disassembly
Cautions: 1. Disconnect the monitor from the power source before disassembly.
2. Follow these directions carefully; never use metal instruments to pry apart the cabinet.
DescriptionPicture DescriptionScrews
1. Place monitor face down on cushioned table.
Remove screws from the Stand.
Remove stand.
3-1
3. Disassembly and Reassemble
DescriptionPicture DescriptionScrews
2. Remove the screws of rear-cover.
3. Lift up the rear-cover.
* Fan is used in 40” only
3-2
DescriptionPicture DescriptionScrews
4. Remove the screws of IP and main board.
* 32” model hasn’t shield case.
5. Remove the speakers and screws of inlet
socket.
3. Disassembly and Reassemble
3-3
3. Disassembly and Reassemble
DescriptionPicture DescriptionScrews
6. Remove the screws of Stand BKLT.
Lift up the Stand BKLT.
7. Remove the Side AV Ass’y (only 46”)
3-4
3. Disassembly and Reassemble
DescriptionPicture DescriptionScrews
8-1. Remove the screws of bracket. (32”)
8-2. Remove the screws of bracket. (40”)
8-3. Remove the screws of bracket. (46”, 52”)
* Caution: Don’t place excessive pressure
on wall mount bracket during
disassembly.
It may become bent or damaged.
3-5
3. Disassembly and Reassemble
DescriptionPicture DescriptionScrews
9. Remove the screws on Panel.
Reassembly procedures are in the reverse order of disassembly procedures.
※
3-6
4. Troubleshooting
4. Troubleshooting
4-1. Troubleshooting
1.
Check the various cable connections rst.
• Check to see if there is a burnt or damaged cable.
• Check to see if there is a disconnected or loose cable connection.
• Check to see if the cables are connected according to the connection diagram.
2.
Check the power input to the Main Board.
3.
Check the Power input to the FRC(Frame Rate Conversion) Board.
Check internal Pattern both of FRC and FBE3 if there is some picture noise.
FRC: Factory mode(Info - MENU - MUTE - power on) -> Advanced Menu -> Option Block -> FRCM ->
TP After DDR Press right button of Remocon.
FBE3: Factory mode(Info - MENU - MUTE - power on_ -> Advanced Menu -> Option Block -> FBE3 -> Patt-Sel ->
Press right button of Remocon.
Case1: FBE3 ok,FRC NG: change the FRC Board Case2: FBE3 NG: change the main Board
Check the LED lamp for source button on front
If this LED blank 100mS frequently then FRC board is defective(communication problem via Main board)
in this case change the FRC board
4-1
4. Troubleshooting
4-1-1. No Power
-
Symptom
Major
checkpoints
-
-
The IP relay or the LEDs on the front panel does not work when connecting the power cord if the cables are
improperly connected or the Main Board or SMPS is not functioning. In this case, check the following:
-
-
-
-
The LEDs on the front panel do not work when connecting the power cord.
The SMPS relay does not work when connecting the power cord.
The units appears to be dead.
Check the internal cable connection status inside the unit.
Check the fuses of each part.
Check the output voltage of SMPS.
Replace the Main Board.
Diagnostics
LAMP off, power indicator
LED red color?
Yes
Does proper DC 13V appear at
1
2
1.25V(B1.2VD), 1.5V, 1.8V(MT_DDRV)
3
pin21,22 of CN801?
Yes
Does proper DC A3.3V appear at
C1131_NACH, C1132_NACH?
Yes
Does proper DC 5V, 3.3V,
appear at C1140, C1169,
C1163, C1167, C1174?
Yes
No
No
No
No
1
3
2
Check a connection a power cable.
Change a Assy PCB Power.
Check a IC1103_NACH.
Change a main PCB ass’y
Check a IC1108, IC1107, IC1109
Change a main PCB ass’y
4-2
Caution
A power is supplied to set?
Make sure to disconnect the power before working on the IP board.
No
Check a other function.
(No picture part)
Replace a lcd panel.
4-1-2. No Video (Analog PC signal)
SymptomAudio is normal but no picture is displayed on the screen.-
Check the PC source
Major
checkpoints
-
Check the SEMT01(MT8226)
-
This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.
-
4. Troubleshooting
2
1
Power Indicator is off.
Lamp on, no video.
Diagnostics
Check a PC source and check
the connection of DSUB cable?
Does the signal appear at C3131,
1
2
CautionMake sure to disconnect the power before working on the IP board.
C3133, C3136(R,G,B)
Does the digital data appear at the
output of LVDS (RA5104~RA5109)?
Check a LVDS cable?
Replace a lcd panel?
Yes
No
Yes
No
Yes
No
Yes
No
Input a analog PC signal and
connected cable(DPMS).
PC cable. Change a PC
cable. Change a main PCB ass’y.
Check a IC5105
Change a main PCB ass’y
Please, Contact Tech support.
4-3
4. Troubleshooting
WAVEFORMS
1
R,G,B Output Signal
4-4
4-1-3. No Video (HDMI - Digital Signal)
SymptomAudio is normal but no picture is displayed on the screen.-
Check the HDMI source
Major
checkpoints
-
Check the SEMT01(MT8226)
-
This may happen when the LVDS cable connecting the Main Board and the Panel is disconnected.
-
4. Troubleshooting
3
2
1
Power Indicator is off.
Lamp on, no video.
Diagnostics
1
2
3
CautionMake sure to disconnect the power before working on the IP board.
Check the connection
of HDMI cable?
Does the digital data appear at
Pin17,18,20,21,23,24 of IC3108?
Does the digital data appear at output
of LVDS (RA5104~RA5109)?
Check the LVDS cable?
Replace the LCD panel?
Yes
No
Yes
No
Yes
No
Yes
No
Input a HDMI cable.
Check a IC3108.
Change a main PCB ass’y.
Check a IC5105.
Change a main PCB ass’y.
Please, Contact Tech support
4-5
4. Troubleshooting
WAVEFORMS
2
3
Digital Output Data
Signal of HDMI(Data)
4-6
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