LCD-Monitor Chassis : LS26TW / LS24TW Model : T260 / T240 / T260N / T240N SERVICE Manual TFT-LCD Monitor Contents T260 / T240 / T260N / T240N Refer to the service manual in the GSPN (see the rear cover) for the more information. 1. Precautions 2. Product specifications 3. Disassembly and Reassemble 4. Troubleshooting 5. Exploded View & Part List 6. Wiring Diagram 7. Schematic Diagram
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4.Troubleshooting...................................................................................................... 4-14-1. Troubleshooting .............................................................................................................. 4-14-2. When the Power Does Not Turn On ............................................................................... 4-24-3. When a blank screen is displayed (Analog) ................................................................... 4-44-4. When a Blank Screen Is Displayed (DVI) - T260/T240 Only .......................................... 4-74-5. Error Examples and Actions ......................................................................................... 4-104-6. Adjustment .................................................................................................................... 4-11
5.ExplodedView&PartList...................................................................................... 5-15-1. Exploded View (25.5”) .................................................................................................... 5-15-2. Parts List ......................................................................................................................... 5-35-3. Exploded View (24”) ....................................................................................................... 5-65-4. Parts List ......................................................................................................................... 5-8
1-1. Safety PrecautionsFollow these safety, servicing and ESD precautions to prevent damage and to protect against potential hazards such as electrical shock.
1-1-1. WarningsFor continued safety, do not attempt to modify the circuit board.
Disconnect the AC power and DC power jack before servicing.
1-1-2. Servicing the LCD MonitorWhen servicing the LCD Monitor, Disconnect the AC line cord from the AC outlet.
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 HazardBefore returning the monitor to the user, perform the following safety checks:
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 monitor.
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.
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).
With the unit completely reassembled, plug the AC line cord directly into a 120V AC outlet. With the unit’s AC switch first 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 NoticesSome 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 identified 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, fire and/or other hazards. Product safety is under review continuously and new instructions are issued whenever appropriate.
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DEVICEUNDERTEST
(READING SHOULD) NOT BE ABOVE 0.5mA
LEAKAGECURRENTTESTER
TEST ALLEXPOSED METALSURFACES
2-WIRE CORD
*ALSO TEST WITHPLUG REVERSED(USING AC ADAPTERPLUG AS REQUIRED) EARTH
1-2. Servicing PrecautionsWARNING: 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: If unforeseen circumstances create conflict between the following servicing precautions and any of the
safety precautions, always follow the safety precautions.
1-2-1 General Servicing PrecautionsAlways 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.
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.
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.
Check the insulation between the blades of the AC plug and accessible conductive parts (examples: metal panels, input terminals and earphone jacks).
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.
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.
1-3. Static Electricity PrecautionsSome 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 field-effect transistors. The following techniques will reduce the incidence of component damage caused by static electricity.
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 monitor.
After removing an ESD-equipped assembly, place it on a conductive surface such as aluminum foil to prevent accumulation of an electrostatic charge.
Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ESDs.
Use only a grounded-tip soldering iron to solder or desolder ESDs.
Use only an anti-static solder removal device. Some solder removal devices not classified as “anti-static” can generate electrical charges sufficient to damage ESDs.
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.
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.
Minimize body motions when handling unpackaged replacement ESDs. Motions such as brushing clothes together, or lifting your foot from a carpeted floor can generate enough static electricity to damage an ESD.
1-4. Installation PrecautionsFor safety reasons, more than two people are required for carrying the product.
Keep the power cord away from any heat emitting devices, as a melted covering may cause fire or electric shock.
Do not place the product in areas with poor ventilation such as a bookshelf or closet. The increased internal temperature may cause fire.
Make sure to turn the power off and unplug the power cord from the outlet before repositioning the product. Also check the antenna cable or the external connectors if they are fully unplugged. Damage to the cord may cause fire or electric shock.
Keep the antenna far away from any high-voltage cables and install it firmly. Contact with the highvoltage cable or the antenna falling over may cause fire or electric shock.
When installing the product, leave enough space (10cm) between the product and the wall for ventilation purposes. A rise in temperature within the product may cause fire.
T260 / T240 Support PC / DVI / HDMI5ms, DC 20000:1 Applied300cd/m2, 170/160(CR>10)USB (1 up, 2 down) optionalHDCP Applied for HDMI/DVI-D Fixed Aspect Ratio SupportSupported camera effects: Black/Sepia/Green/Blue
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T260N / T240N Support PC5ms, DC 20000:1 Applied300cd/m2, 170/160(CR>10)USB (1 up, 2 down) optionalHDCP Applied for HDMI/DVI-D Fixed Aspect Ratio SupportSupported camera effects: Black/Sepia/Green/Blue
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Specifications
Item Description
Model T260 / T240 T260N / T240N
LCD Panel TFT-LCD panel, RGB vertical stripe, normally black transmissive,25.5-Inch viewable, 0.2865(H)x0.2865(V) mm pixel pitch
TFT-LCD panel, RGB vertical stripe, normally black transmissive,24-Inch viewable, 0.270(H)x0.270(V) mm pixel pitch
4-1. TroubleshootingBefore troubleshooting, setup the PC ‘s display as below. • Resolution: 1920 x 1200 • H-frequency: 75 kHz • V-frequency: 60 Hz
If no picture appears, make sure the power cord is correctly connected.
Check the following circuits. • No raster appears: Function PBA. Main PBA. IP-Board • 5V develop but no screen : Main PBA • 13V, 5V does not develop: IP-Board, Main PBA
Symptom The LED on the front panel of the monitor does not work when the power is connected and the Power button is pressed.
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Major checkpoints
Check if the Power switch on the rear panel of the monitor has been turned on.Check the SMPS fuse and the IP-Board output power.Check the connection between the IP-Board and the Main Board inside the monitor.Check the power part of the Main Board and check if a similar symptom appears at another output terminal.
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Diagnostics
Main Board Front
CN600IC604
IC802
Yes
Replace No the IP board.NoIs DC 5V measured at pin 3,4,5 of CN600 when pin 6, 7 is DC 5V?
Is DC 5V measured at pin 1 of IC604 when pin 3 is DC 3.3V?
Check the circuits related to IC604
No
Yes
Replace the Main Board.
Check the Function Ass’y
Yes
Is DC 5V measured at pin 4 of IC802 when pin 1 is DC 5V?
Check the circuits related to IC802
No
Caution Make sure to disconnect the power before working on the IP board.
Symptom The LED power is on but no picture is displayed on the screen when the D-SUB cable is connected
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Major checkpoints
Even though the LED power turns on, the screen is blank when connecting the VGA cable.Check the D-sub cable connections.Check whether the LVDS cable is connected correctly to the panel.Check whether the lamp connector of the panel is connected correctly to the IP board.
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Diagnostics
Main Board Front
CN400
IC202X200
R115R116
R106R110
U2593
Yes
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Check the signal cables and their connections.
YesCheck and replace related
circuits if necessary.NoCheck if X200 is oscillating normally.
Check if R, G and B inputs are measured at R106, R110 and U2593.
Check the input part.No
Yes
Check if Hsync and Vsync are measured at R115 and R116.
Check the input part.No
Yes
Check if Hsync and Vsync are measured at pins 32 and 33 of IC202.
Check the circuit around IC202.
No
②
YesDo output signals appear at pins 8 to 30
of CN400?No
Check the input part.
③
Yes
Is DC 5V measured at pins 1, 2, and 3of the CN400?
No Check the +5V_Panel signaland the BL_EN signal.
Yes
Replace the LCD panel.
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Caution Make sure to disconnect the power before working on the IP board.
4-4. When a Blank Screen Is Displayed (DVI) - T260/T240 Only
Symptom The LED power is on but no picture is displayed on the screen when the DVI cable is connected.-
Major checkpointsCheck if the DVI cable has been connected.Check if the LVDS cable has been properly connected to the LCD panel.Check if the Inverter board has been connected properly to the lamp connector of the LCD panel.
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Diagnostics
Main Board Front
CN400
X200
Yes
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Check the signal cables andtheir connections.
Yes
Check and replace related circuits if necessary.
NoCheck if X200 is oscillating normally.
Check if R, G and B signals are measured at R142~R145, R148~R151.
Check the circuit around IC300.
No
Yes
Check if the output signal appears at pins 8 to 30 of CN400.
Check the circuit around IC202.
No
Yes
Replace the LCD panel.
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Caution Make sure to disconnect the power before working on the IP board.
4-6-1. Service Adjustment ConditionsPrecautions before a Service Adjustment. 1) Check whether the devices for the service adjustment are operating normally. 2) Secure a space that is sufficiently wide for disassembling the monitor. 3) Prepare a soft mat on which the monitor will be disassembled.
Entering Service Mode.
Entering: Menu Brightness 0 Contrast 0 Hold down the Enter button for five (5) seconds.
Exiting: Power OFF Power ON
Auto Color Adjustment Use a 16 gray-scale or gray-black-mixed pattern for the video input. 1) For the OSD Language, select the language at the top.. 2) Press and hold the OSD “(Enter/Source)” for 5 seconds.
4-6-2. Firmware DownloadYou have to complete the post-operation using a MICOM Jig (RS232 Jig) after replacing the Main Board.You can update the Micom using a MICOM Jig (RS232 Jig).
RequirementsThe following devices are required for adjusting the monitorA Computer with Windows 95, 98, 2000, XP or NT.MTI-2059 DDC Manager Jig-RS232 Jig
Entering the Micom Code You have to complete the operation using the DDC Manager after replacing the Main Board. Connect devices as shown below.You can update the Micom using the DDC Manager.
Entering the EDID 1. Install the Winddc.exe program onto the PC.2. Click the Winddc icon.3. Select Open.4. Select Port #15. Open a DDC file. *File Name “SMT260A-1/SMT240A-1.ddc” → Analog DDC “SMT260D-1/SMT240D-1.ddc” → Digital DDC “SMT260H-1/SMT240H-1.ddc” → HDMI DDC6. Click Next (OK).
4-6-3. Service Function Spec.1. 1. Set the Brightness and Contrast to 0.2. Press and hold the Enter and Source keys.3. The SVC Function OSD appears.*To exit from the SVC Function OSD, you have to turn the power off.
Panel Information
Software VersionMICOM Checksum
The SVC Function OSD consists of a 103 (Horizontal) x 82 (Vertical) Grid.The SVC Function OSD consists of Panel Information, the Software Version and the Micom Checksum.
Navigating Menus 1. Press the (▼) key to move up and press the (▲) key to change the value of a selected.
Replacing the Panel When replacing the panel: After replacing the panel, select the Panel Ch. No. item and press and hold the MENU key
for 5 seconds. The Panel Ch. No. increases by 1 and the Panel On Time is reset to 0. At the same time, the Panel Cycle is also reset to 0.
Other Functions 1. Auto Auto : On / Off2. PixelShift : On / Off3. Country : English / Korean / Chinese / Japanese4. HDCP HP-DVI : On / Off5. HDCP HP-HDMI : On / Off6. HotPlug Time : 5~50 (Default 9 : 0.9sec)
3. Disassembly and ReassembleThis section describes the disassembly and reassembly sequences for this monitor.
WARNING: As this monitor has parts that are sensitive to static electricity, be careful when handling them.
3-1. Disassembly Cautions: 1. Turn the monitor off before beginning the disassembly process.
2. Disassemble the monitor carefully as directed in the following procedures. 3. When disassembling the monitor, do not use any metal tools except for the provided jig.
Part Description Picture Description Screws
Stand
1. Placeasoftclothonthefloorandplace the monitor on it so that the front of the monitor is on the cloth.
2. Remove 2 screws.
Rear Cover
3. To remove the rear cover, insert a jigorflatscrewdriverintobothjiggrooves at the bottom. Lift up the cover until you hear a ‘snapping’ sound. (Remove the two SANPs at the bottom.)
6. Remove the Shield Lamp using a pointed tool and then remove the four (4) lamp wires.
Caution : When removing the SHIELD-LAMP, do not remove the GASKET-SHEET from the SHIELD-LAMP. If the GASKET-SHEET is damaged, you will not be able to receive free service.