SAFETY PRECAUTIONS
NOTICE: Comply with all cautions and safety-relatedLeakage Current Hot Che ck
notes located on or inside the cabinet and on the chasPlug the AC is orcord directly into a 120V AC 60Hz outlet (do
picture tube.not use an isolated transformer for this check). Turn the
AC power ON. Using a Leakage Current Tester
WARNING: Since the chasis of this receiver is connected
(Simpson?s Model 229 or equivalent), measure for current
to one side of the AC power supply during operation,
from all exposed metal parts of the cabinet (antennas,
whenever the receiver is plugged in, service should not be
screwheads, overlays, control shafts, etc.). Any current
attempted by anyone unfamiliar with the precautions
measured must not exceed 0.5 milliamps.
necessary when working on this type of receiver.
The following precautions should be observed:
1. Do not install, remove, or handle the picture tube in any(READING
manner unless shatterproof goggles are worn. PeopleSHOULD NOT BE
ABOVE 0.5mA)
not so equipped should be kept away from the picture
tube while handling.
DEVICE LEAKAGE
UNDER CURRENT
TESTER
2. When service is required, an isolation transforTESTmerTEST ALL
should be inserted between power line and the receiverEXPOSED METAL
SURFACES+-
before any service is performed on a ?HOT? chassis
receiver.
2-WIRE CORD
3. When replacing a chassis in the receiver, all protective
devices must be put back in place, such as barriers,ALSO TEST WITH
nonmetallic knobs, adjustment and compartmentPLUG REVERSED
(USING AC ADAPTER
covershields, isolation resistors, capacitors, etc.EARTH
PLUG AS REQUIRED)GROUND
4. When service is required, observe the original lead
dress in the high voltage circuitry area.
5. Always use the manufacturer?s replacement
components. Critical components as indicated on the
circuit diagram should not be replaced by anotherAC LEAKAGE TEST
manufacturer?s. Furthermore, where a short circuit has
ANY MEASUREMENTS NOT WITHIN THE LIMITS
occurred, replace those components that indicate
OUTLINED ABOVE ARE INDICATIVE OF A
evidence of overheating.
POTENTIAL SHOCK HAZARD AND MUST BE
6. Before returning a serviced receiver to the CORREcustomCTED BEer, theFORE RETURNING THE
service technician must thoroughly test the REunit CEIVERto be TO THE CUSTOMER.
certain that it is completely safe to operate without
danger of electrical shock, and be sureHigh volt that noage
protective device built into the receiver has This recbecomeeiver is provided with a hold down circuit for clearly
defective, or inadvertently defeated during sindicervicating that ving.oltage has increased in excess of a
predetermined value. Comply with all notes described in
Therefore, the following checks should be perthiformed fors service manual regarding this hold down circuit when
the continued protection of the customer and servserviicing, sceo that this hold down circuit is operated
technician.correctly.
Leakage Current Cold CheckServiceman Warning
With the AC plug removed from the 120V AC 60Hz source,
With minimum BRIGHTNESS, CONTRAST,
place a jumper across the two plug prongs. Turn the AC
SHARPNESS, and COLOR, the operating high voltage in
power switch ON. Using an insulation tester (DC500V),
this receiver is lower than 28.30kV ?1.25kV. In case any
connect one lead to the jumpered AC plug and touch the
component having influence on the high voltage is
other lead to each exposed metal part (antennas,
replaced, confirm that high voltage with minimum
screwheads, metal overlays, control shafts, etc.),
BRIGHTNESS, CONTRAST, SHARPNESS, and COLOR
particularly any exposed metal part having a return path to
is lower than 28.30kV ?1.25kV. To measure high voltage
the chassis should have a minimum resistor reading of
use a High Impedance High Voltage meter. Connect (-) to
0.24MW and a maximum resistor reading of 12MW . Any
chassis earth and (+) to the CRT ANODE button. (See the
resistance value below or above this range indicates an
connection diagram on page 4.)
abnormality which requires corrective action. An exposed
metal part not having a return path to the Notchasse: iTurn s wilpower switclh OFF without fail before the
indicate an open circuit.connection to the Anode Button
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ACEC
