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SAFETY PRECAUTIONS
NOTICE:
Observe all cautions and safety related notes located inside the receiver cabinet and on the receiver chassis.
WARNING
1.
2.
Operation of this receiver outside the cabinet or with the cover removed presents a shock hazard from the receiver
power supplies. Work on the receiver should not be attempted by anyone who is not thoroughly familiar with the
precautions necessary when working on high-voltage equipment.
Do not install, remove or handle the picture tube in any manner unless shatter-proof goggles are worn. People not so
equipped should be kept away while the picture tube is being handled. Keep the picture tube away from the body
while handling.
X-RADIATION WARNING
The surface of the picture tube may generate X-Radiation. Take precautions when servicing and, if possible, the use
of a lead apron is recommended for shielding while handling.
When replacing the picture tube, use only the designated replacement part since it is a critical component with
regard to X-Radiation as noted above. No high-voltage adjustments are provided. The high-voltage specification is
described on the cover page.
LEAKAGE CURRENT CHECK
Before returning the receiver to the customer, it is recommended that leakage current be measured according to the
following methods.
. Cold Check
With the AC plug removed from the AC source, place a jumper across the two AC plug prongs. Turn the receiver AC
switch on. Using an ohm-meter, connect one lead to the AC plug and touch the other lead to each exposed metal
part (antennas, handle bracket, metal cabinet, screwheads, metal overlays, control shafts, etc.), particularly any
exposed metal part having a return path to the chassis. Exposed metal parts having a return path to the chassis
should have a minimum resistance reading of 1 megohm. Any resistance below this value indicates an abnormality
which requires corrective action. Exposed metal parts not having a return path to the chassis will indicate an open
circuit.
Hot Check
Use the circuit in Fig. 1 to perform this test.
(1) With switch S1 open, connect the receiver to the measuring circuit. Immediately after connection, measure the
leakage current using both positions of switch S2, and with the switching devices in the receiver in all of their
operating positions.
(2) Switch $1 is then closed, energizing the receiver. Immediately after closing the switch, measure the leakage
current using both positions of switch S2, and with the switching devices in the receiver in all of their operating
positions. Current measurements of ites (1) and (2) are to be repeated after the receiver has reached thermal
stabilization. The leakage current must not be more than 0.5 milliampere.
AC Milliammeter
Receiver
|
AC aes
(Grounding)
Open
Insulating Table
Grounding Supply Conductor
5
Fig. 1
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