Samsung SPT4388PF, Service Manual

Page: 4 / 99

Precautions
1-2 Samsung Electronics
1-1 Safety Precautions (Continued)
1 5 . 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.
1 6 . 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.
1 7 . 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.
1 8 . 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.
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.
1 0 . 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.
1 1 . 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.
1 2 . 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 o n l y i f
an isolation transformer inserted between
the receiver and the power source.
1 3 . 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
a l t e r e d .
1 4 . 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.