DW2U
SAFETY PRECAUTIONS
NOTICE: Comply with all cautions and safety-related notesLeakage Current Hot Check
located on or inside the cover case and on the chassis or plasmaPlug the AC line cord directly into a 120V AC outlet. (Do not use an
module.isolation transformer during this test.) Use a leakage current
WARNING: Since the chassis of this receiver is connected totester or a metering system that complies with the American
one side of the AC power supply during operation, whenever theNational Standards Institute (ANSI) C101.0 Leakage Current
receiver is plugged in service should not be attempted by any-for Appliances. In the case of the PDP monitor set the AC
one unfamiliar with the precautions necessary when working onswitch first in the ON position and then in the OFF position,
this type of receiver.measure from across Line 1 and Line 2 of the three plug
prongs, do not connect with the third prong, which is physical
1. When service is required, an isolation transformer should beground, to all exposed metal parts of the instrument
inserted between power line and the receiver before any(antennas, handle bracket, metal cabinet, screw heads,
service is performed on a ?HOT? chassis receiver.metallic overlays, control shafts, etc.), especially any exposed
metal parts that offer an electrical return path to the chassis.
2. When replacing a chassis in the receiver, all the protectiveAny current measured must not exceed 0.5 MIU. Reverse the
devices must be put back in place, such as barriers, non-instrument power cord plug in the outlet and repeat test.
metallic knobs, insulating cover-shields, and isolation
resistors, capacitors, etc.
3. When service is required, observe the original lead dress.
AC LEAKAGE TEST
4. Always use manufacturer?s replacement components. Critical
components as indicated on the circuit diagram should not be
(READING
replaced by another manufacturer?s. Furthermore, where aSHOULD NOT
short circuit has occurred, replace those components thatLEAKAGEBE ABOVE 0.5MIU)
CURRENT
indicate evidence of over heating.DEVICETESTER
UNDER
TEST
5. Before returning a serviced receiver to the customer, the
TEST ALL
service technician must thoroughly test the unit to be certain
EXPOSED
that it is completely safe to operate without danger of electricalMETAL SURFACES
shock, and be sure that no protective device built into the
3-WIRE CORDEARTH
receiver by the manufacturer has become defective, orGROUND
inadvertently defeated during servicing.ALSO TEST WITH PLUG
REVERSED
Therefore, the following checks should be performed for the(USING AC ADAPTER
PLUS AS REQUIRED)
continued protection of the customer and service technician.
Leakage Current Cold CheckANY MEASUREMENTS NOT WITHIN THE LIMITS OUTLINED
With the AC plug removed from the 120V AC 60Hz source,ABOVE ARE INDICATIVE OF A POTENTIAL SHOCK HAZARD
place a jumper across Line 1 and Line 2 of the three plugAND MUST BE CORRECTED BEFORE RETURNING THE
prongs, do not connect with the third prong, which is physicalRECEIVER TO THE CUSTOMER.
ground.
Using an insulation tester (DC500V), connect one of its leads
to the AC plug jumper and touch with the other lead each
exposed metal part (antennas, screwheads, metal overlays,
control shafts, etc.), particularly any exposed metal part
having a return path to the chassis should have a resistor
reading over 4M&. Any resistance value below this range
indicates an abnormality which requires corrective action. An
exposed metal part not having a return path to the chassis will
indicate an open circuit.
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