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Precaution
1.Precaution
Follow these safety, servicing and ESD precautions to prevent damage and protect against potential hazards such
as electrical shock and X-rays.
1-1 SafetyPrecautions
1. Be sure that all of the built-in protective devices are replaced.
2. When reinstalling the chassis and its assemblies, be sure to restore all protective devices, including control
knobs and compartment covers.
3. Make sure that there are no cabinet openings through which people--particularly children--might insert fingers
and contact dangerous voltages. Such openings include the spacing between the picture tube and the cabinet
mask, excessively wide cabinet ventilation slots, and improperly fitted back covers.
4. Design Alteration Warning:
Never alter or add to the mechanical or electrical design of the unit.
Example: Do not add auxiliary audio or video connectors. Such alterations might create a safety hazard.
Also, any design changes or additions will void the manufacturer's warranty.
5. Leakage Current Hot Check (Fig. 1-1):
Warning: Do not use an isolation transformer during this
test. Use a leakage-current tester or a metering system DEVICE
LEAKAGE (READING
CURRENT SHOULD NOT BE
that complies with American National Standards Institute UNDER TESTER ABOVE 0.5mA)
TEST
(ANSI C101.1, Leakage Current for Appliances), and TEST ALL
Underwriters Laboratories (UL Publication UL1410, EXPOSED METAL
SURFACES
59.7). 2-WIRE CORD
ALSO TEST WITH
With the unit completely reassembled, plug the AC line PLUG REVERSED
(USING AC EARTH
cord directly into a 120V AC outlet. With the unit's AC ADAPTER PLUG GROUND
AS REQUIRED)
switch first in the ON position and then OFF, measure
the current between a known earth ground (metal water
pipe, etc.) and all exposed metal parts. Examples:
Handle brackets, metal cabinets, screwheads and control shafts. The current measured should not exceed 0.5
milliamp. Reverse the powerplug prongs in the AC outlet and repeat.
6. Insulation Resistance Cold Check:
(1) With the unit's AC plug disconnected from the AC Antenna
Terminal
source, connect an electrical jumper across the two AC
prongs. (2) Set the power switch to ON. (3) Measure
Exposed
the resistance between the shorted AC plug and any Metal Part
exposed metallic parts.
ohm
Example: Screwheads, antenna, control shafts or handle Ohmmeter
brackets.
If any of the exposed metallic parts has a return path
to the chassis, the measured resistance should be between 1 and 5.2 megohms. If there is no return path, the
measured resistance should be "infinite." If the resistance is outside these limits, a shock hazard might exist.
See Fig. 1-2
Samsung Electronics 1-1
Precaution
7. Components, parts and wiring that appear to have overheated or that are otherwise damaged should be
replaced with parts that meet the original specifications. Always determine the cause of damage or overheating,
and correct any potential hazards
8. Observe the original lead dress, especially near the following areas: Antenna wiring, sharp edges, and
especially the AC and high voltage power supplies. Always inspect for pinched, out-of-place, or frayed wiring.
Do not change the spacing between components and the printed circuit board. Check the AC power cord for
damage. Make sure that no wires or components touch thermally hot parts.
9. Product Safety Notice:
Some electrical and mechanical parts have special safety-related characteristics which might not be obvious
from visual inspection. These safety features and the protection they give might be lost if the replacement
component differs from the original--even if the replacement is rated for higher voltage, wattage, etc.
10. Components that are critical for safety are indicated in the circuit diagram by shading, or . Use
replacement components that have the same ratings, especially for flame resistance and dielectric strength
specifications. A replacement part that does not have the same safety characteristics as the original might
create shock, fire or other hazards.
1-2 Samsung Electronics
Precaution
1-2 ServicingPrecautions
1. Servicing precautions are printed on the cabinet. Follow them.
2. Always unplug the unit's AC power cord from the AC power source before attempting to: (a) Remove or reinstall
any component or assembly, (b) Disconnect an electrical plug or connector, (c) Connect a test component in
parallel with an electrolytic capacitor.
3. Some components are raised above the printed circuit board for safety. An insulation tube or tape is sometimes
used. The internal wiring may be clamped to prevent contact with thermally hot components. Reinstall all such
elements to their original position.
4. After servicing, always check that the screws, components and wiring have been correctly reinstalled.
Make sure that the portion around the serviced part has not been damaged.
5. Check the insulation between the blades of the AC plug and accessible conductive parts (examples: metal
panels, input terminals and earphone jacks).
6. Insulation Checking Procedure: Disconnect the power cord from the AC source and turn the power switch ON.
Connect an insulation resistance meter (500V) 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.
7. Never defeat any of the B+ voltage interlocks. Do not apply AC power to the unit (or any of its assemblies)
unless all solid-state heat sinks are correctly installed.
8. 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.
First read the "Safety Precautions" section of this manual. If some unforeseen circumstance
creates a conflict between the servicing and safety precautions, always follow the safety
precautions.
Samsung Electronics 1-3
Precaution
1-3 PrecautionsforElectrostaticallySensitiveDevices(ESDs)
1. Some semiconductor ("solid state") devices are easily damaged by static electricity.
Such components are called Electrostatically Sensitive Devices (ESDs). Examples include integrated circuits
and some field-effect transistors. The following techniques will reduce the occurrence of component damage
caused by static electricity.
2. 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. (Be sure to
remove it prior to applying power--this is an electric shock precaution.)
3. After removing an ESD-equipped assembly, place it on a conductive surface such as aluminum foil to prevent
accumulation of electrostatic charge.
4. Do not use freon-propelled chemicals. These can generate electrical charges that damage ESDs.
5. Use only a grounded-tip soldering iron when soldering or unsoldering ESDs.
6. Use only an anti-static solder removal device. Many solder removal devices are not rated as "anti-static" (these
can accumulate sufficient electrical charge to damage ESDs).
7. 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.
8. 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.
9. Minimize body motions when handing unpackaged replacement ESDs. Motions such as brushing clothes
together, or lifting a foot from a carpeted floor can generate enough static electricity to damage an ESD.
1-4 Samsung Electronics