Samsung ltm225w service manual

TFT-LCD TV/MONITOR

Chassis Model PD22UO LTM225W

Manual

SERVICE

TFT-LCD TV/MONITOR CONTENTS

1. Precautions

2. Product Specifications

3. Disassembly & Reassembly

4. Alignment & Adjustments

5. Troubleshooting

6. Exploded View & Parts List

7. Electrical Parts List

8. Block Diagram

9. Wiring Diagram

10. Schematic Diagrams

11. Panel Description

CONFIDENTIAL

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 Monitor

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 monitor 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 monitor.

2. Inspect all protective devices such as nonmetallic control knobs, insulating materials, cabinet backs, adjustment and compartment covers or shields, isolation resistor-capacitor 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).

Figure 1-1. Leakage Current Test Circuit

4. 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 Notices

Some electrical and mechanical parts have special safety-related 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.

LTM225W 1-1

CONFIDENTIAL

1 Precautions

Follow these safety, servicing and ESD precautions to prevent damage and to protect against potential hazards such as electrical shock.

1-1 Safety Precautions

DEVICE UNDER TEST

TEST ALL

EXPOSED METAL

SURFACES

(READING SHOULD

NOT BE ABOVE 0.5mA)

LEAKAGE CURRENT

TESTER

2-WIRE CORD

ALSO TEST WITH

PLUG REVERSED (USING AC ADAPTER PLUG AS REQUIRED)

EARTH

GROUND

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.

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 wriststrap device. To avoid a shock hazard, be sure to remove the wrist strap before applying power to the monitor.

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 sufficient 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 classified as “anti-static” can generate electrical charges sufficient to damage ESDs.

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 the blades 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.

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 floor can generate enough static electricity to damage an ESD.

1 Precautions

1-2 LTM225W

CONFIDENTIAL

1-3 Electrostatically Sensitive Devices (ESD) 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 field-effect transistors. The following techniques will reduce the incidence of component damage caused by static electricity.

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: If unforeseen circumstances create conflict between the following servicing precautions and any of the

safety precautions, always follow the safety precautions.

2 Product Specifications

2-1 Specifications

CONFIDENTIAL

Item

LCD Panel TFT-LCD panel, RGB vertical stripe, normally

Scanning Frequency Horizontal : 30 KHz ~ 61 KHz (Automatic)

Vertical : 56 Hz ~ 75 Hz (Automatic)

Display Colors 16.7 Million colors

Maximum Resolution Horizontal : 1280 Pixels

Vertical : 720 Pixels

Input Video Signal Analog 0.7 Vp-p ± 5% positive at 75 Ω, internally terminated

Input Sync Signal Type : Separate H/V

Level : TTL level

Maximum Pixel Clock rate 70 MHz

Active Display Horizontal/Vertical

AC power voltage & Frequency

Power Consumption 120 W (Max)

Dimensions Unit (W x D x H) 23.6 x 7.3 x 18.4 Inches (600 x 185 x 468 mm)

Carton (W x D x H) 27.6 x 21.8 x 10.2 Inches (702 x 553 x 260 mm)

487.68 mm / 274.32 mm

AC 90 ~ 264 Volts, 60 / 50 Hz ± 3 Hz

Description

Black, 22-Inch viewable, 0.381 mm pixel pitch

Weight (Unit/Gross) 8.8 Kg (19.4 Ibs) / 15.3 Kg (33.7 Ibs)

Environmental Considerations Operating Temperature : 50 °F ~ 104 °F (10 °C ~ 40 °C)

Humidity : 10 % ~ 80 % Storage Temperature : -4 °F ~ 113 °F (-20 °C ~ 45 °C) Humidity : 5 % ~ 95 %

Tuning Frequency Synthesize

TV System

Antenna Input 75Ω, Coaxial Cable

Sound Characteristic – MAX Internal Speaker Out : Right => 7W

– Woofer Speaker (Option) : 500 mV RMS at 20 ~ 150 Hz

– BASS Control Range : -12 dB~ + 12 dB – TREBLE Control Range : -12 dB~ + 12 dB – Headphone Out: 5mW max (400m Vrms) – Output Frequency : RF => 80 Hz ~ 15 KHz

System NTSC-M

Sound STEREO

Left => 7W

A/V => 80 Hz ~ 15 KHz

LTM225W 2-1

2 Product Specifications

12 345 67 8

9 10111213141516

17 18 19 20 21 21 22 23

C1 C2

C3 C4

2-2 Pin Assignments

2-2-1 DVI-I (Analog & Digital)

(Ref) DVI-D : Digital only

D-SUB : Analog only

DVI-I Receptacle Connector Front View

2-2-2 DVI-I (Digital video interface)

Table 2-1 Combined analog and digital connector pin assignments

CONFIDENTIAL

Pin No.

Signal Assignment

T.M.D.S. Data2-

T.M.D.S. Data2+

T.M.D.S. Data2/4 Shield

T.M.D.S. Data4-

T.M.D.S. Data4+

DDC Clock

DDC Data

Analog Vertical Sync.

T.M.D.S. Data1-

T.M.D.S. Data1+

T.M.D.S. Data1/3 Shield

Pin No.

Signal Assignment

Pin No.

T.M.D.S. Data3-

T.M.D.S. Data3+

+5V Power

Ground

(return for +5V, HSync. and VSync.)

Hot Plug Detect

T.M.D.S. Data0-

T.M.D.S. Data0+

T.M.D.S. Data0/5 Shield

T.M.D.S. Data5-

T.M.D.S. Data5+

Signal Assignment

T.M.D.S. Clock Shield

T.M.D.S. Clock+

T.M.D.S. Clock-

Analog Red

Analog Green

Analog Blue

Analog Horizontal Sync.

Analog Ground

(analog R,G&B return)

2-2 LTM225W

2 Product Specifications

CONFIDENTIAL

2-2-3 DVD, DTV

RCA Green

RCA Blue

RCA Red

RCA White

RCA Red

GND

Pb (Cb)

GND

Pr (Cr)

GND

Audio L

GND

Audio R

GND

2-2-4 S-Video

1 2 3 4 5

Separate

GND

C GND GND

2-2-5 A/V

RCA Yellow

RCA White

RCA Red

CVBS

Audio L

GND

Audio R

GND

LTM225W 2-3

2 Product Specifications

CONFIDENTIAL

2-3 Timing Chart

This section of the service manual describes the timing that the computer industry recognizes as standard for computer-generated video signals.

2-3-1 LCD Panel Mode : 1 mode

✻ N/I : Non-Interlaced, I : Interlaced

2-4 LTM225W

2 Product Specifications

2-3-2 Supported Modes (1)

CONFIDENTIAL

µs µs µs µs µs µs µs µs

LTM225W 2-5

2 Product Specifications

2-3-2 Supported Modes (2)

CONFIDENTIAL

µs µs µs µs µs µs µs µs

2-6 LTM225W

LTM225W 3-1

CONFIDENTIAL

3 Disassembly and Reassembly

This section of the service manual describes the disassembly and reassembly procedures for the LTM225W monitor.

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.

1. Remove 4 screws from the rear cover.

2. Remove the stand from LCD-TV.

3. Remove 1 screw from the rear cover.

CONFIDENTIAL

3 Disassembly and Reassembly

3-2 LTM225W

3-2 Reassembly

Reassembly procedures are in the reverse order of disassembly procedures.

4. Insert a screw driver into the right and left holes on the stand’s upper groove respectively. Lift up the right & left side.

5. Pull the rear cover.

CONFIDENTIAL

LTM225W 4-1

4 Alignments and Adjustments

4-1 General Alignment Instuction

1. Usually, a color TV-VCR needs only slight touch-up adjustment upon installation. Check the basic characteristics such as height, horizontal and vertical sync.

2. Use the specified test equipment or its equivalent.

3. Correct impedance matching is essential.

4. Avoid overload. Excessive signal from a sweep generator might overload the front-end of the TV. When inserting signal markers, do not allow the marker generator to distort test result.

5. Connect the TV only to an DC power source with voltage and frequency as specified on the backcover nameplate.

6. Do not attempt to connect or disconnect any wire while the TV is turned on. Make sure that the power cord is disconnected before replacing any parts.

7. To protect aganist shock hazard, use an isolation transformer.

4 Alignments and Adjustments

4-2 LTM225W

CONFIDENTIAL

4-2 Factory Mode Adjustments

4-2-1 Entering Factory Mode

1. To enter “Service Mode” Press the remote -control keys in this sequence :

- If you do not have Factory remote - control

- If you have Factory remote - control

4-2-2 Factory Mode Tree

4 Alignments and Adjustments

LTM225W 4-3

CONFIDENTIAL

Memo

4 Alignments and Adjustments

4-4 LTM225W

CONFIDENTIAL

LTM225W 5-1

5 Troubleshooting

5-1 No Power

Does proper DC 14V

appear at Pin 1 of CN923?

Check SMPS’s part and adapter.

Yes

IC811 is bad.

Change main assy.

(BN94-00397A)

IC802 is bad.

Change main assy.

(BN94-00397A)

IC805 is bad.

Change main assy.

(BN94-00397A)

IC806 is bad.

Change main assy.

(BN94-00397A)

IC812 is bad.

Change main assy.

(BN94-00397A)

IC804 or IC967 are bad.

Change main assy.

(BN94-00397A)

IC807 is bad.

Change main assy.

(BN94-00397A)

IC803 is bad.

Change main assy.

(BN94-00397A)

Yes

Does proper DC 3.3V_A

appear at Pin 2 of IC811?

Does proper DC 2.5V_A

appear at Pin 3 of IC802?

Does proper DC 3.3V_B

appear at Pin 1 of IC805?

Does proper DC 2.5V_B

appear at Pin 3 of IC806?

Does proper DC 5V_A

appear at Pin 2 of IC812?

Does proper DC 5V_A

appear at Pin 2 of

IC804 and Pin 2 of IC967?

Does proper DC 12V

appear at Pin 2 of IC807?

Does proper DC 8V_A

appear at Pin 3 of IC803?

1-1

1-2

1-3

1-4

1-5

1-6

1-7 1-8

1-9

1-10

5 Troubleshooting

5-2 LTM225W

CONFIDENTIAL

WAVEFORMS

1-8 1-9

1-10

1-2 1-3

1-4

1-1

1-5 1-6

1-7

5 Troubleshooting

LTM225W 5-3

CONFIDENTIAL

5-2 No Video (PC Signal)

Power indicator is green.

Yes

Replace the LCD_Panel with new one.

Yes

Check CN714 and

FFC(BN41-00240A) cable.

Does the signal

appear at C491, C489,

C488, R424 and R425 of

R, G, B, H, V?

Yes

IC350 is bad.

Change main PCB assy.

(BN94-00397A)

R354 is bad.

Change main PCB assy.

(BN94-00397A)

Check is X201.

IC200 is bad.

Change main PCB assy.

(BN94-00397A)

RA301~RA306 are bad. Change main PCB assy.

(BN94-00397A)

Does the signal appear at

IC956 ~ IC961?

Yes

Does the signal

appear at R354?

Yes

Does the clock pulse

appear at X201?

Yes

Does the signal appear at

RA301~RA306?

Yes

Power indicator is green.

Does the signal

appear at CN924?

2-1

2-3

2-2 2-4 2-5

2-6

2-7

2-8

2-9

2-10

5 Troubleshooting

5-4 LTM225W

CONFIDENTIAL

WAVEFORMS

2-1 2-2

2-4 2-5

2-10

2-9

2-7

2-8

2-6

2-3

CONFIDENTIAL

5 Troubleshooting

LTM225W 5-5

Replace the LCD_Panel with new one.

5-3 No Picture (Tuner CVBS, AV CVBS, S-Video)

Check CN712 and

FFC(3809-001406) cable.

Does the signal

appear at C744(Tuner),

C746(AV), C747(SVHS_Y)

and C748(SVHS_C)?

Yes

IC722 is bad.

Change main PCB assy.

(BN94-00397A)

IC200 is bad.

Change main PCB assy.

(BN94-00397A)

Check is X201

IC200 is bad.

Change main PCB assy.

(BN94-00397A)

RA301~RA306 are bad. Change main PCB assy.

(BN94-00397A)

Does the signal appear

at R214(Tuner), R215(AV),

R219(SVHS_Y) and

R224(SVHS_C) in IC722?

Yes

Does the signal

appear at R308(Blue),

R310(Green) and R311(Red)?

Yes

3-1

3-3

3-2 3-4

3-5 3-7

3-6 3-8

3-9

3-11

3-10

Yes

Does the clock pulse

appear at X201?

Yes

Does the signal appear at

RA301~RA306?

Yes

Power indicator is green.

Does the signal

appear at CN924?

3-12

3-13

3-14

+ 44 hidden pages