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Precautions
1-1 Safety Precautions (Continued)
9. High voltage is maintained within specified
limits by close-tolerance, safety-related
components and adjustments.
If the high
voltage exceeds the specified limits, check
each of the special components.
10. Design Alteration Warning:
Never alter or add to the mechanical or
electrical design of this 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.
11. Hot Chassis Warning:
Some TV receiver chassis are electrically
connected directly to one conductor of the
AC power cord. If an isolation transformer
is not used, these units may be safely
serviced only if the AC power plug is
inserted so that the chassis is connected to
the ground side of the AC source.
To confirm that the AC power plug is
inserted correctly, do the following: Using
an AC voltmeter, measure the voltage
between the chassis and a known earth
ground. If the reading is greater than 1.0V,
remove the AC power plug, reverse its
polarity and reinsert. Re-measure the
voltage between the chassis and ground.
12. Some TV chassis are designed to operate
with 85 volts AC between chassis and
ground, regardless of the AC plug polarity.
These units can be safely serviced only if
an isolation transformer inserted between
the receiver and the power source.
13. Some TV chassis have a secondary
ground system in addition to the main
chassis ground. This secondary ground
system is not isolated from the AC power
line. The two ground systems are
electrically separated by insulating
material that must not be defeated or
altered.
14. 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.
15.
16.
17;
18.
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 leads and components do not touch
thermally hot parts.
Picture Tube Implosion Warning:
The picture tube in this receiver employs
"integral implosion" protection. To
ensure continued implosion protection,
make sure that the replacement picture
tube is the same as the original.
Do not remove, install or handle the
picture tube without first putting on
shatterproof goggles equipped with side
shields. Never handle the picture tube by
its neck. Some "in-line" picture tubes are
equipped with a permanently attached
deflection yoke; do not try to remove
such "permanently attached" yokes from
the picture tube.
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.
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.
Samsung Electronics
1-2 Servicing Precautions
Precautions
1.
Servicing precautions are printed on the
cabinet. Follow them.
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.
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.
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).
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 I megohm.
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.
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 Precautions for Electrostatically Sensitive Devices (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.
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.)
After removing an ESD-equipped assembly,
place it on a conductive surface such as
aluminum foil to prevent accumulation of
electrostatic charge.
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.
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.
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.
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.
Minimize body motions when handling
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.
Samsung Electronics
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