Samsung GH15H Schematic

TFT-LCD MONITOR

GH15H*

Manual

SERVICE

TFT-LCD MONITOR CONTENTS

1. Precautions

2. Product Specifications

3. Disassembly & Reassembly

4. Troubleshooting

5. Exploded View & Parts List

6. Electrical Parts List

7. Block Diagram

8. Wiring Diagram

9. Schematic Diagrams

10. 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.

3. When the chassis is operating, semiconductor
heatsinks are potential shock hazards.

1-1-2 Servicing the LCD Monitor

1. When servicing the LCD Monitor, remove the static
charge by connecting a 10k ohm resistor in series
with an insulated wire (such as a test probe)
between the chassis and the anode lead.
(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.

GH15H* 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 GH15H*

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 devices are integrated circuits and some field­effect 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.

CONFIDENTIAL

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 ~ 61 kHz (Referring ~ Timing chart, Page 2-3, 2-4)

Vertical : 50 Hz ~ 75 Hz (Referring ~ Timing chart, Page 2-3, 2-4)
Display Colors 16,003,008 colors
Maximum Resolution Horizontal : 1024 Pixels Vertical : 768 Pixels
Input Video Signal Analog, 0.714 Vp-p ± 5% positive at 75 Ω, internally terminated
Input Sync Signal Type: Seperate H/V sync, Composite H/V, Sync-on-Green, automatic synchronization

without external switch of sync type

Level: TTL level
Maximum Pixel Clock rate 80 MHz
Active Display Horizontal/Vertical 304.1 mm / 228.1 mm
AC power voltage & Frequency AC 90 ~ 264 Volts, 60/50 Hz ~ 12V/3A
Power Consumption 25 W (normal)
Dimensions

Unit (W x D x H)
With Simple Stand

15.4 x 15.1 x 6.8 Inches (391.4 x 383.6 x 173 mm)

Without Simple stand

15.4 x 11.5 x 2.5 Inches (391.4 x 292.8 x 64.0 mm)

With Pivot Stand

15.4 x 15.1 x 6.8 Inches (391.4 x 383.6 x 173 mm)

15.4 x 17.1 x 6.8 Inches (391.4 x 433.6 x 173 mm)

Without Pivot Stand

15.4 x 11.5 x 2.5 Inches (391.4 x 292.8 x 64.0 mm)
Weight (Net/Gross) 4.2 kg (9.3 lbs) / 5.2 kg (11.5 lbs)
Environmental Considerations Operating Temperature : 50 °F ~ 104 °F (10 °C ~ 40 °C)

Humidity : 10 % ~ 80 %
Storage Temperature : 13 °F ~ 113 °F (-25 °C ~ 45 °C)
Humidity : 5 % ~ 95 %

•GH15H* complies with SWEDAC (MPR II) recommendations for reduced
electromagnetic fields.

•Designs and specifications are subject to change without prior notice.

GH15H* 2-1

Item

Description

CONFIDENTIAL

2 Product Specifications

2-2 GH15H*

2-2 Pin Assignments

Sync
Type

Pin No.

15-Pin Signal Cable Connector

Separate Composite Sync-on-green

1
2
3
4
5
6
7
8

9
10
11
12
13
14
15

Red
Green
Blue
GND
GND (DDC Return)
GND-R
GND-G
GND-B
No Connection
GND-Sync./Self Test
GND
DDC Data
H-Sync.
V-Sync.
DDC Clock

Red
Green
Blue
GND
GND (DDC Return)
GND-R
GND-G
GND-B
No Connection
GND-Sync./Self Test
GND
DDC Data
H/V-Sync.
Not Used
DDC Clock

Red
Green + H/V Sync.
Blue
GND
GND (DDC Return)
GND-R
GND-G
GND-B
Not Used
GND-Sync./Self Test
GND
DDC Data
Not Used
Not Used
DDC Clock

CONFIDENTIAL

31.469

31.778

3.813

1.589

26.058

0.318

70.086

14.268

0.064

1.716

11.504

0.985

25.175

Positive
Negative
Separate

fH (kHz)
A µsec
B µsec
C µsec
D µsec
E µsec
fV (Hz)
O msec
P msec
Q msec
R msec
S msec
Clock

Frequency
(MHz)

Polarity
H.Sync

V.Sync
Remark

IBM

2 Product Specifications

GH15H* 2-3

QRS

P

O

Video

Sync

Sync

Horizontal

Vertical

CDE

P

O

B

A

Video

Sync

Sync

Separate Sync

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.

C D

A

O

E

B

P

Video

Sync

Sync

Video

Q R S

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

VGA3/60 Hz

640 x 480

640/72 Hz
640 x 480

640/75 Hz
640 x 480

800/56 Hz
800 x 600

800/60 Hz
800 x 600

VGA1/70 Hz

640 x 350

VGA2/70 Hz

720 x 400

Table 2-1 Timing Chart

31.469

31.777

3.813

1.589

26.058

0.318

70.087

14.268

0.064

0.858

13.155

0.191

28.322

Negative

Positive

Separate

31.469

31.778

3.813

1.589

26.058

0.318

59.940

16.683

0.064

0.794

15.761

0.064

25.175

Negative
Negative
Separate

37.861

26.413

1.270

3.810

20.825

0.508

72.809

13.735

0.079

0.528

13.100

0.026

31.500

Negative
Negative
Separate

37.500

26.667

2.032

3.810

20.317

0.508

75.000

13.333

0.080

0.427

12.800

0.027

31.500

Negative
Negative
Separate

35.156

28.444

2.000

3.556

22.222

0.667

56.250

17.778

0.057

0.626

17.067

0.028

36.000

Positive
Negative
Separate

37.879

26.400

3.200

2.200

20.000

1.000

60.317

16.579

0.106

0.607

15.840

0.026

40.000

Positive
Positive

Separate

Mode

VESA

Timing

CONFIDENTIAL

2 Product Specifications

2-4 GH15H*

fH (kHz)
A µsec
B µsec
C µsec
D µsec
E µsec
fV (Hz)
O msec
P msec
Q msec
R msec
S msec
Clock

Frequency
(MHz)

Polarity
H.Sync

V.Sync
Remark

VESA

800/72 Hz
800 x 600

800/75 Hz
800 x 600

640/67 Hz
640 x 480

832/75 Hz
832 x 624

Table 2-1 Timing Chart (Continued)

48.077

20.800

2.400

1.280

16.000

1.120

72.188

13.853

0.125

0.478

12.480

0.770

50.000

Positive
Positive

Separate

46.875

21.333

1.616

3.232

16.162

0.323

75.000

13.333

0.064

0.448

12.800

0.021

49.500

Positive
Positive

Separate

35.000

28.571

2.116

3.175

21.164

2.116

66.667

15.000

0.086

1.114

13.714

0.086

30.240

Negative
Negative
Separate

49.726

20.110

1.117

3.910

14.524

0.559

74.551

13.414

0.060

0.784

12.549

0.020

57.284

Negative
Negative
Separate

Mode

MAC

Timing

QRS

P

O

Video

Sync

Sync

Horizontal

Vertical

CDE

P

O

B

A

Video

Sync

Sync

Separate Sync

C D

A

O

E

B

P

Video

Sync

Sync

Video

Q R S

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

1024/70Hz

1024x768

56.476

17.707

1.813

1.920

13.653

0.320

70.069

14.272

0.106

0.513

13.599

0.053

75.000

Negative
Negative
Separate

1024/75Hz

1024x768

60.023

16.660

1.219

2.235

13.003

0.203

75.029

13.328

0.050

0.466

12.795

0.017

78.750

Positive
Positive

Separate

1024/60Hz

1024x768

48.363

20.677

2.092

2.462

15.754

0.369

60.004

16.666

0.124

0.600

15.880

0.062

65.000

Negative
Negative
Separate

CONFIDENTIAL

3 Disassembly and Reassembly

This section of the service manual describes the disassembly and reassembly procedures for the
GH15H* monitor.

WARNING: This monitor contains electrostatically sensitive devices. Use with 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.

3-1-1 Removing the Stand

1. Remove 4 screws in the hinge area.

2. Disconnect Power Cord and Signal Cable.

3. Pry it off the back of the monitor.

3-1-2 Main Body Disassembly

1. Remove 2 screws on the two corner of the
Rear Cover.

2. Remove Rear Cover from the Front Cover.

3. Remove 4 screws on the Shield and remove
the shield.

4. Disconnect Inverter wire, Function PCB wire
and Interface wire.
Remove 3 screws on the Main PCB and
remove 2 screws on the D sub shield.

5. Remove 3 screws on the power PCB and
remove 2 screws on the Inverter PCB.

6. Remove the Main PCB Assembly.

7. Remove 3 screws on the Function PCB from
locking area of Function knob and remove
Function PCB.

3-1-3 Standard Stand Disassembly

1. Remove 2 screws from the Stand front.

2. Remove 7 screws from the Stand Bottom.

3. Remove Stand Rear from the Stand assembly.

4. Remove 5 screws from the Stand assembly.

5. Remove the Neck front from the Stand
assembly.

6. Remove 2 screws from the Stand assembly.

7. Remove Neck Rear from the Stand assembly.

8. Remove 4 screws from the Stand assembly.

GH15H* 3-1

3 Disassembly and Reassembly

3-2 Replacement Order of Lamp Assemblies

CONFIDENTIAL

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

2. Push down the stopper and
slide the lamp unit.

3. Please take out the lamp
unit from the LCD

module.

3-2 GH15H*

3 Disassembly and Reassembly

* Replacement of lamp unit should be done at the power off state and recommanded clean

bench condition.

CONFIDENTIAL

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

3-3 Reassembly

Reassembly procedures are in the reverse order of Disassembly procedures.

GH15H* 3-3