LG 42LB550A, Руководство по обслуживанию

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Many el Many el ectrical ectrical and mechanic and mechanic al parts al parts in this in this chassis chassis have spec have spec ial safety ial safety -related characteristi -related characteristi cs. cs. These parts These parts are identified are identified by by in the in the
Schematic Diagram and Schematic Diagram and Exploded View. Exploded View.
It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent It is essential that these special safety parts should be replaced with the same components as recommended in this manual to prevent
Shock, Fire, or other Hazards. Shock, Fire, or other Hazards.
Do not modify the Do not modify the original design without permission of manufacturer. original design without permission of manufacturer.
General Guidance General Guidance
An An isolation Transformer should always be used isolation Transformer should always be used during the during the
servicing of a receiver whose chassis is not isolated from the AC servicing of a receiver whose chassis is not isolated from the AC
power line. Use a transformer of adequate power rating as this power line. Use a transformer of adequate power rating as this
protects the technician from accidents resulting in personal injury protects the technician from accidents resulting in personal injury
from electrical shocks. from electrical shocks.
It will also protect the receiver and it's components from being It will also protect the receiver and it's components from being
damaged by accidental shorts of the circuitry that may be damaged by accidental shorts of the circuitry that may be
inadvertently introduced during the service operation. inadvertently introduced during the service operation.
If any fuse (or Fusible Resistor) in this TV receiver is blown, If any fuse (or Fusible Resistor) in this TV receiver is blown,
replace it with the specified. replace it with the specified.
When replacing a high wattage resistor (Oxide Metal Film Resistor, When replacing a high wattage resistor (Oxide Metal Film Resistor,
over 1 W), keep the resistor 10 mm away from PCB. over 1 W), keep the resistor 10 mm away from PCB.
Keep wires away from high voltage or high temperature parts. Keep wires away from high voltage or high temperature parts.
Before returning the receiver to the Before returning the receiver to the customer, customer,
always perform an always perform an AC leakage current check AC leakage current check
Leakage Current Hot Check Leakage Current Hot Check (See below Figure) (See below Figure)
Plug the AC cord directly into the AC outlet. Plug the AC cord directly into the AC outlet.
Do not use a Do not use a line Isolation Transform line Isolation Transform er during this check. er during this check.
Connect 1.5 K / 10 watt resistor in parallel with a 0.15 uF capacitor Connect 1.5 K / 10 watt resistor in parallel with a 0.15 uF capacitor
between a known good earth ground (Water Pipe, Conduit, etc.) between a known good earth ground (Water Pipe, Conduit, etc.)
and the exposed metallic parts. and the exposed metallic parts.
Measure the AC voltage across the resistor using AC voltmeter Measure the AC voltage across the resistor using AC voltmeter
with 1000 ohms/volt or with 1000 ohms/volt or more sensitivity more sensitivity . .
Reverse plug the AC cord into the AC outlet and repeat AC voltage Reverse plug the AC cord into the AC outlet and repeat AC voltage
measurements for each exposed metallic part. Any voltage measurements for each exposed metallic part. Any voltage
measured must not exceed 0.75 volt RMS which is corresponds to measured must not exceed 0.75 volt RMS which is corresponds to
0.5 mA. 0.5 mA.
In case any measurement is out of the limits specified, there is In case any measurement is out of the limits specified, there is
possibility of shock hazard and the set must be checked and possibility of shock hazard and the set must be checked and
repaired before it is returned to the customer. repaired before it is returned to the customer.
Leakage Current Hot Check circuit Leakage Current Hot Check circuit
IMPORTANT SAFETY NOTICE IMPORTANT SAFETY NOTICE
SAFETY PRECAUTIONS SAFETY PRECAUTIONS