Samsung LT15M23C Schematic

TFT-LCD TV

Chassis Model
VE15JO LT15M23C

Manual

SERVICE

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

Samsung Electronics Co.,Ltd.

416, Maetan-3Dong, Yeongtong-Gu, Suwon City, Kyungki-Do,
Korea, 443-742
Printed in Korea
P/N : BN82-00103Q-00
URL : http://itself.sec.samsung.co.kr/

❈ 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.

1 Precautions

LT15M23C 1-1

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 Ser vicing 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).

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 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.

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 Ser vicing

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 wrist-strap 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 LT15M23C

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 Ser vicing 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

LT15M23C 2-1

2 Product Specifications

2-1 Specifications

LCD Panel TFT-LCD panel, RGB vertical stripe, normaly white, 15-Inch viewable, 0.297 mm pixel pitch

Scanning Frequency Horizontal : 30 kHz ~ 60 kHz (Automatic)

Vertical : 56 Hz ~ 75 Hz (Automatic)

Display Colors 16.2 Million colors

Maximum Resolution Horizontal : 1024 Pixels

Vertical : 768 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

Active Display
Horizontal/Vertical

AC power voltage & Frequency

AC 120V, ~ 60 Hz

Power Consumption 40 W

Dimensions(W x D x H)

Set 14.2 x 2.5 x 13.3 Inches (360.2 x 64.2 x 338.6 mm)(State of stand disassembled)

14.2 x 7.6 x 15.5 Inches (360.2 x 192.9 x 396.5 mm)(State of stand installed)

Package 18.4 x 17.0 x 6.0 Inches (467 x 431 x 153 mm)

Weight

Set 3.6 Kg (7.9 Ibs)

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 %

TV System

Antena Input 75Ω, Coaxial Cable

– MAX Internal speaker Output : Right => 2.5W

Left => 2.5W

Sound Characteristic

– Headphone Out: 10mW max (3.50 Stereo Jack 32)
– Output Frequency : RF => 80 Hz ~ 15 kHz at -3dB

A/V => 80 Hz ~ 20 kHz at -3dB

Item

Description

304.1 mm / 228.1 mm

Tunning Frequency Synthesize

System NTSC-M

Sound MONO, STEREO, SAP

2 Product Specifications

2-2 LT15M23C

2-2 Pin Assignments

2-2-1 D1/D2 Connector

RCA White

RCA Red

Audio L

GND

Audio R

GND

2-2-2 DTV SOUND

Pin

Separate

ArrangementPin NO.

1
2
3
4
5

GND

Y

C
GND
GND

2-2-3 S-Video

1
2
3
4
5
6
7
8

9
10
11
12
13
14

Y

Y_GND

Pb

PB_GND

Pr

Pr_GND

Preliminary Line1

Line1
Line5

Preliminary Line2

Line3

Switch GND

Preliminary Line3

Switch

2 Product Specifications

LT15M23C 2-3

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15

RCA White

RCA Red

CVBS

Audio L

GND

Audio R

GND

2-2-4 A/V

RCA Yellow

Pin

Separate

Red

Green

Blue
GND

GND (DDC Return)

GND-Red

GND-Green

GND-Blue

No Connection

GND-Sync / Self Test

GND

DDC Data

H - Sync
V - Sync

DDC Clock

2-2-5 D-SUB

2 Product Specifications

2-4 LT15M23C

Separate Sync

2-3 Timing Char t

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

A : Line time total B : Horizontal sync width O : Frame time total P : Vertical sync width

C : Back porch D : Active time Q : Back porch R : Active time

E : Front porch S : Front porch

H/V Composite Sync

Sync-on-Green

VGA

LT15M23C

LT15M23C

LT15M23C

LT15M23C

SVGA

XGA

Table 2-1 Timing Chart

Mode

Resolution

Horizontal

Frequency(kHz)

Vertical

Frequency(Hz)

Pixel

Clock

Frequency(MHz)

Sync

Polarity(H/V)

720X400

640X480

640X480

800X600

800X600

1024X768

1024X768

31.496

31.496

37.500

46.875

37.879

48.363

60.023

70.087

59.940

75.000

75.000

60.317

60.004

75.029

28.322

25.175

31.500

49.500

40.000

65.000

78.750

- / +

- / -

- / -

+ / +

+ / +

- / -

+ / +

3 Disassembly and Reassembly

LT15M23C 3-1

3 Disassembly and Reassembly

This section of the service manual describes the disassembly and reassembly procedures for the
LT15M23C TFT-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 any metal instrument except provided
jig to separate 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 stand from the LCD TV.

2. Remove 2 screws from the rear cover and lift up
rear cover.

3. Remove 11 screws from the boards and disconnect
inverter cables from the boards.

4. Disconnect LVDS cable, function cable and
speaker cable from the board.

5. Lift up the boards and remove 8 screws from the
panel shield.

!

!

3 Disassembly and Reassembly

3-2 LT15M23C

6. Lift up the panel shield and disconnect panel from
the front.

1. After confirm there is nothing on the desk, turn the
LCD module over and put it on a flat desk set to
the ground.

2. Remove 2 screws for the lamp unit.

3. Slide the lamp unit out. Please take out the lamp
unit from the LCD module.

3-2 Replacement Order of Lamp Assemblies

Slide the lamp unit out.

Slide the lamp unit out.

3 Disassembly and Reassembly

LT15M23C 3-3

3-3 Reassembly

Reassembly procedures are in the reverse order of disassembly procedures.

4. Please fix the new lamp units on the LCD module :
opposite process 2 and 3.

MEMO

3 Disassembly and Reassembly

3-4 LT15M23C

4 Alignments and Adjustments

LT15M23C 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 transform.

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

4-2 LT15M23C

4 Alignments and Adjustments

LT15M23C 4-3

4 Alignments and Adjustments

4-4 LT15M23C

7. Test Pattern ( Test Pattern of VCTi)

1) VCTi

2) Toshiba

3) Gray Bar

4) Gray

5) Green

6) Color Bar

7) Cross

8. Bus Stop

- Bus stop is used data communication.

9. Chcek Sum

- Display the current check sum size of the MICOM.

10. Reset

- Initializes the data in the MICOM.

11. T-VNC15NJP-0910 2004/06/08

- Display the MICOM program version.

4-2-3 White Balance

High Low

267, 263 265, 260

x, y x, y