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CONFIDENTIAL
TFT-LCD MONITOR
GH15H*
SERVICE Manual
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 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
1-1-1 Warnings
1. For continued safety, do not attempt to modify the (READING SHOULD
circuit board. NOT BE ABOVE 0.5mA)
2. Disconnect the AC power and DC Power Jack
before servicing. DEVICE
LEAKAGE
CURRENT
UNDER TESTER
3. When the chassis is operating, semiconductor TEST
TEST ALL
heatsinks are potential shock hazards. EXPOSED METAL
SURFACES
1-1-2 Servicing the LCD Monitor 2-WIRE CORD
1. When servicing the LCD Monitor, remove the static
charge by connecting a 10k ohm resistor in series ALSO TEST WITH
PLUG REVERSED
with an insulated wire (such as a test probe) (USING AC ADAPTER
PLUG AS REQUIRED)
between the chassis and the anode lead. EARTH
GROUND
(Disconnect the AC line cord from the AC outlet.)
2. It is essential that service technicians have an Figure 1-1. Leakage Current Test Circuit
accurate voltage meter available at all times. Check
the calibration of this meter periodically. 4. With the unit completely reassembled, plug the AC
line cord directly into a 120V AC outlet. With the
1-1-3 Fire and Shock Hazard unit's AC switch first in the ON position and then
Before returning the monitor to the user, perform the OFF, measure the current between a known earth
following safety checks: ground (metal water pipe, conduit, etc.) and all
exposed metal parts, including: metal cabinets,
1. Inspect each lead dress to make certain that the
screwheads and control shafts. The current
leads are not pinched or that hardware is not
measured should not exceed 0.5 milliamp. Reverse
lodged between the chassis and other metal parts in
the power-plug prongs in the AC outlet and repeat
the monitor.
the test.
2. Inspect all protective devices such as nonmetallic
control knobs, insulating materials, cabinet backs,
adjustment and compartment covers or shields, 1-1-4 Product Safety Notices
isolation resistor-capacitor networks, mechanical
Some electrical and mechanical parts have special
insulators, etc.
safety-related characteristics which are often not
3. Leakage Current Hot Check (Figure 1-1): WARNING: evident from visual inspection. The protection they give
Do not use an isolation transformer during this test. may not be obtained by replacing them with
Use a leakage current tester or a metering system components rated for higher voltage, wattage, etc. Parts
that complies with American National Standards that have special safety characteristics are identified by
Institute (ANSI C101.1, Leakage Current for ! on schematics and parts lists. A substitute
Appliances), and Underwriters Laboratories (UL replacement that does not have the same safety
characteristics as the recommended replacement part
Publication UL1410, 59.7).
might create shock, fire and / or other hazards. Product
safety is under review continuously and new
instructions are issued whenever appropriate.
GH15H* 1-1
1 Precautions
CONFIDENTIAL
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.
1-2-1 General Servicing Precautions
1. Always unplug the unit's AC power cord from the 4. Check the insulation between the blades of the AC
AC power source and disconnect the DC Power plug and accessible conductive parts (examples:
Jack before attempting to: metal panels, input terminals and earphone jacks).
(a) remove or reinstall any component or assembly, 5. Insulation Checking Procedure: Disconnect the
(b) disconnect PCB plugs or connectors, (c) connect power cord from the AC source and turn the power
a test component in parallel with an electrolytic switch ON. Connect an insulation resistance meter
capacitor. (500 V) to the blades of the AC plug.
2. Some components are raised above the printed The insulation resistance between each blade of the
circuit board for safety. An insulation tube or tape AC plug and accessible conductive parts (see
is sometimes used. The internal wiring is above) should be greater than 1 megohm.
sometimes clamped to prevent contact with
6. Always connect a test instrument's ground lead to
thermally hot components. Reinstall all such
the instrument chassis ground before connecting
elements to their original position.
the positive lead; always remove the instrument's
3. After servicing, always check that the screws, ground lead last.
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
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 field-
effect transistors. The following techniques will reduce the incidence of component damage caused by static electricity.
components or assemblies, drain the electrostatic 6. Do not remove a replacement ESD from its
charge from your body by touching a known earth protective package until you are ready to install it.
ground. Alternatively, wear a discharging wrist- Most replacement ESDs are packaged with leads
strap device. To avoid a shock hazard, be sure to that are electrically shorted together by conductive
remove the wrist strap before applying power to foam, aluminum foil or other conductive materials.
the monitor. 7. Immediately before removing the protective
2. After removing an ESD-equipped assembly, place it material from the leads of a replacement ESD,
on a conductive surface such as aluminum foil to touch the protective material to the chassis or
prevent accumulation of an electrostatic charge. circuit assembly into which the device will be
3. Do not use freon-propelled chemicals. These can installed.
generate electrical charges sufficient to damage Caution: Be sure no power is applied to the
ESDs. chassis or circuit and observe all
4. Use only a grounded-tip soldering iron to solder or other safety precautions.
desolder ESDs.
5. Use only an anti-static solder removal device. Some 8. Minimize body motions when handling
solder removal devices not classified as "anti-static" unpackaged replacement ESDs. Motions such as
can generate electrical charges sufficient to damage brushing clothes together, or lifting your foot from
ESDs. a carpeted floor can generate enough static
electricity to damage an ESD.
1-2 GH15H*
CONFIDENTIAL
2 Product Specifications
2-1 Specifications
Item Description
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