Samsung LW20M11C Service manual

TFT-LCD TV

Chassis Model MU20EO LW20M11C

SERVICE

Manual

TFT-LCD TV 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. PCB Layout

11. Schematic Diagrams

12. Panel Description

❈ This Service Manual is a property of Samsung

Electronics Co., Ltd. Any unauthorized use of Manual can be punished under applicable International and/or domestic law.

Samsung Electronics Co.,Ltd.

416, Maetan-3Dong, Paldal-Gu, Suwon City, Kyungki-Do, Korea, 442-742 Printed in Korea P/N : BN82-00109F-00 URL : http://itself.sec.samsung.co.kr/

2 Product Specifications

2-1 Specifications

Item

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

Display Colors 16.7 Million colors

Maximum Resolution Horizontal : 640 Pixels

Vertical : 480 Pixels

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

Input Sync Signal Type : Seperate H/V

Level : TTL level

Maximum Pixel Clock rate 80 MHz

Active Display Horizontal/Vertical

AC power voltage & Frequency

Power Consumption 65 W

Dimensions (W x D x H)

Set Package 27.6 x 11.5 x 22.2 Inches (700 x 293 x 563 mm)

Weight (Set/Package) 9.81 Kg (21.62 Ibs) / 11.5 Kg (25.4 Ibs)

408 mm(H) / 306 mm(V)

AC 100 ~ 240 Volts, 50 Hz ~ 60 Hz

23.4 x 9.9 x 19.3 Inches (594 x 252 x 489.5 mm) / 23.4 x 3.5 x 16.8 Inches (594 x 90 x 427 mm)

Description

white, 20-Inch viewable, 0.64 mm pixel pitch

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

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

Tunning Frequency Synthesize

TV System

Antena Input 75Ω, Coaxial Cable

– MAX Internal speaker Output : Right => 3W

Sound Characteristic

– 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 PAL / SECAM / NT 4.43-BG / DK / I

Sound STEREO

Left => 3W

A/V => 80 Hz ~ 15 kHz

LW20M11C 2-1

2 Product Specifications

2-2 Pin Assignments

2-2-1 Scart

Pin No.

Items

Audio Out

Audio In

Audio Out

Audio Common GND

Blue GND

Audio In

Blue In

Function S/W

Green GND

Pin No.

Items

No Connection

Green In

No Connection

Red GND

F/B GND

Red In

RGB F/B

Video Output GND

Video Input GND

2-2-2 S-Video

1 2 3 4 5

Separate

GND

C GND GND

2-2-3 A/V

RCA Yellow

RCA White

RCA Red

CVBS

Audio L

GND

Audio R

GND

2-2 LW20M11C

3 Disassembly and Reassembly

This section of the service manual describes the disassembly and reassembly procedures for the LW20M11C TFT-LCD monitors.

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.

3. R/Cover opening jig : BH81-00001A

1. Place monitor face down on cushioned table. Remove 4 screws from grip on the stand and remove the stand.

2. Remove 5 screws from the back cover and remove the back cover.

3. Disconnect speaker cable and IR cable from the shield PCB. Remove 13 screws from the shield PCB.

4. Lift up the shield PCB and remove 17 screws from the MAIN boards.

5. Disconnect TTL cable and inverter cables from the MAIN boards.

LW20M11C 3-1

3 Disassembly and Reassembly

6. Lift up the boards and remove 10 screws form the shield panel.

7. Remove the shield panel.

3-2 Reassembly

Reassembly procedures are in the reverse order of disassembly procedures.

❈ Inverter cable may be inserted to any connector on the monitor board for assemblin.

3-2 LW20M11C

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 transform.

LW20M11C 4-1

4 Alignments and Adjustments

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

4-2 LW20M11C

4 Alignments and Adjustments

LW20M11C 4-3

4 Alignments and Adjustments

Memo

4-4 LW20M11C

5 Troubleshooting

5-1 No Power

Does proper DC 14V/5V appear at

DC jack connected to CN120?

Yes

Does proper DC 5V

appear at Pin 2 of IC102?

Yes

Does proper DC 2.5V

appear at Pin 2 of IC106?

Yes

Does proper DC 14V

appear at Pin 5 of IC108?

Check FT101 and FT103.

Check IC103 and IC102.

Check IC106.

Check IC108.

Yes

LW20M11C 5-1

Does proper DC 5V

appear at FT107?

Yes

Check IC401.

Check IC108.

5 Troubleshooting

WAVEFORMS

1 2 3

5-2 LW20M11C

5-2 No Picture (TV, Video, S-Video, DVD)

5 Troubleshooting

Check C452 (TV)

Check C453 (Video)

Check C454 (S-Video)

Check C456 (DVD)?

Yes

Check the IC401.

Check the input signal.

WAVEFORMS

LW20M11C 5-3

5 Troubleshooting

5-3 No Sound

Does the signal appear at

Pin 67 (Tuner sound signal) and

Pin 53, 54 (Video sound) and

Pin 56, 57 (DVD Sound)

of IC501 (MSP3425)?

Yes

(RF) Check the Pin 8 of CN701.

(Video Sound) Check the CN903.

(DVD Sound) Check the CN905.

Does the signal appear at Pin 27,

28 of IC501 (MSP3425)?

Yes

Does the signal appear

at Pin16, 19, 2 and 5 of CN651?

Yes

Replace the speaker.

Check the Pin 3 of IC501 and

related circuit of IC501.

Check the IC651 (Audio amp)

and related circuit of IC651.

5-4 LW20M11C

+ 30 hidden pages