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Many electrical and mechanical parts in this chassis have special safety-related characteristics. These parts are identified by
the Schematic Diagram and Replacement Parts List.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to
prevent X-RADIA TION, Shock, Fire, or other Hazards.
Do not modify the original design without permission of manufacturer.
General Guidance
An lsolation T ransformer should always be used during
the servicing of a receiver whose chassis is not isolated from
the AC power line. Use a transformer of adequate power rating
as this protects the technician from accidents resulting in
personal injury from electrical shocks.
It will also protect the receiver and it's components from being
damaged by accidental shorts of the circuitary that may be
inadvertently introduced during the service operation.
If any fuse (or Fusible Resistor) in this TV receiver is blown,
replace it with the specified.
When replacing a high wattage resistor (Oxide Metal Film
Resistor, over 1W), keep the resistor 10mm away from PCB.
Keep wires away from high voltage or high temperature parts.
Due to high vacuum and large surface area of picture tube,
extreme care should be used in handling the Picture T ube .
Do not lift the Picture tube by it's Neck.
X-RAY Radiation
Warning:
The source of X-RA Y RADIA TION in this TV receiver is the
High Voltage Section and the Picture T ube.
For continued X-RAY
the Replacement Parts List.
To determine the presence of high voltage, use an accurate
high impedance HV meter.
Adjust brightness, color, contrast controls to minimum.
Measure the high voltage.
The meter reading should indicate
23.5 ! 1.5KV: 14-19 inch, 26 ! 1.5KV: 19-21 inch,
29.0 ! 1.5KV: 25-29 inch, 30.0 ! 1.5KV: 32 inch
If the meter indication is out of tolerance, immediate service
and correction is required to prevent the possibility of
premature component failure.
Before returning the receiver to the customer,
always perform an AC leakage current check on the exposed
metallic parts of the cabinet, such as antennas, terminals, etc.,
to be sure the set is safe to operate without damage of
electrical shock.
SAFETY PRECAUTIONS
IMPORT ANT SAFETY NOTICE
RADIATION
protection, the
Leakage Current Cold Check(Antenna Cold Check)
With the instrument AC plug removed from AC source,
connect an electrical jumper across the two AC plug prongs.
Place the AC switch in the on positioin, connect one lead of
ohm-meter to the AC plug prongs tied together and touch other
ohm-meter lead in turn to each exposed metallic parts such as
antenna terminals, phone jacks, etc.
If the exposed metallic part has a return path to the chassis, the
measured resistance should be between 1MΩ and 5.2MΩ.
When the exposed metal has no return path to the chassis the
reading must be infinite.
Any other abnormality that exists must be corrected before the
receiver is returned to the customer.
Leakage Current Hot Check
Plug the AC cord directly into the AC outlet.
Do not use a line Isolation T ransformer during this check.
Connect 1.5K/10watt resistor in parallel with a 0.15uF capacitor
between a known good earth ground (Water Pipe, Conduit, etc.)
and the exposed metallic parts.
Measure the AC voltage across the resistor using AC
voltmeter with 1000 ohms/volt or more sensitivity.
Reverse plug the AC cord into the AC outlet and repeat AC
voltage measurements for each esposed metallic part. Any
voltage measured must not exceed 0.75 volt RMS which is
corresponds to 0.5mA.
In case any measurement is out of the limits sepcified, there is
possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer.
Leakage Current Hot Check circuit
To Instrument's
exposed
METALLIC PARTS
CANADA: LG Electronics Canada, Inc. 550 Matheson
Boulevard East Mississauga, Ontario L4Z 4G3
USA
: LG Customer Interactive Center
P.O.Box 240007, 201 James Record Road
Huntsville, AL 35824
Digital TV Hotline 1-800-243-0000
- 2 -
(See below Figure)
AC Volt-meter
Good Earth Ground
such as WATER PIPE,
CONDUIT etc.
0.15uF
1.5 Kohm/10W
in
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