Samsung HPT4254 - 42" Plasma TV Service Manual Download

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1. Make sure all protective devices are properly installed

including non-metallic handles and compartment covers
when installing or re-installing the chassis or chassis
assemblies.

2. Make sure that no gaps exist between the cabinets for

children to insert their fingers in to prevent children from
receiving electric shocks. Gaps mentioned above include
ventilation holes between the PDP module and the cabi-
net mask, and the improper installation of the rear cabi-
net.

Errors may occur when the resistance is below 1.0

over 5.2

In these cases, make sure that the device is repaired
before sending it back to the customer.

3. Check for Electricity Leakage (Figure 1-1)

Warning: Do not use an insulated transformer for check-
ing the leakage. Use only those current leakage testers
or mirroring systems that comply with ANSIC 101.1 and
the Underwriter Laboratory's specifications (UL1410,
59.7).

Fig. 1-1 AC Leakage Test

4. A high voltage is maintained within the specified limits

using safety parts, calibration and tolerances. When
voltage exceeds the specified limits, check each special
part.

5. Warning for Engineering Changes:

Never make any changes or additions to the circuit
design or the internal part for this product.
Ex: Do not add any audio or video accessory
connectors. This might cause physical damage.
Furthermore, any changes or additions to the original
design/engineering will invalidate the warranty.

6. Warning - Hot Chassis:

Some TV chassis are directly connected to one end of
the AC power cord for electrical reasons.
Without insulated transformers, the product can only be
repaired safely when the chassis is connected to the
earth end of the AC power source.

To make sure the AC power cord is properly connected,
follow the instructions below. Use the voltmeter to
measure the voltage between the chassis and the
earth ground. If the measurement is over 1.0V, unplug
the AC power cord and change the polarity before re-
inserting it. Measure the voltage between the chassis
and the ground again.

7. Some TV chassis are shipped with an additional sec-

ondary grounding system. The secondary system is
adjacent to the AC power line. These two grounding
systems are separated in the circuit using an unbreak-
able/unchangeable insulation material.

8. When any parts, material or wiring appear overheated or

damaged, replace them with new immediately. When
any damage or overheating is detected, correct this
immediately and make a regular check of possible
errors.

9. Check for the original shape of the lead, especially that

of the antenna wiring, any sharp edges, the AC power
and the high voltage power. Carefully check if the wiring
is too tight, incorrectly placed or loose. Never change the
space between the part and the printed circuit board.
Check the AC power cord for possible damages. Keep
the part or the lead away from any heat-emitting
materials.

Precaution

Samsung Electronics

1-1

LEAKAGE

CURRENT

TESTER

DEVICE

UNDER

TEST

TEST ALL

EXPOSED METAL

SURFACES

2-WIRE CORD

ALSO TEST WITH

PLUG REVERSED

(USING AC ADAPTER

PLUG AS REQUIRED)

EARTH

GROUND

(READING SHOULD

NOT BE ABOVE

0.5mA)

To avoid possible damage or electric shocks or exposure to radiation, follow the instructions below with regard to safety, instal-
lation, service and ESD.

1. Precaution

1-1 Safety Precautions