Samsung 2220WM - SyncMaster - 22" LCD Monitor, Service Manual

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5
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
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.
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 mega-ohm.
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.
1-3 Static Electricity 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. 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.
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.