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46EXlB
1
SAFETY
PRECAUTIONS
1. Before returning an instrument to the customer, always
make a safety check of the entire instrument, including,
but not limited to the following items:
a. Be sure that no built-in protective devices are defec-
tive and/or have been deleted during servicing. (1)
Protective shields are provided on this chassis to pro-
tect both the technician and the customer. Correctly
replace all missing protective shields, including any
removed for servicing convenience. (2) When rein-
stalling the chassis and/or other assembly in the
cabinet, be sure to put back in place all protective
devices, including, but not limited to, nonmetallic con-
trol knobs, insulating fishpapers,
adjustment
and
compartment
covers/shields, and isolation resistor/
capacitor networks. Do not operate this instrument
or permit it to be operated
without
all protective
devices correctly
installed and functioning.
Ser-
vicers who defeat safety features or fail to perform
safety
checks may be liable for any resulting
damage.
b. Be sure that there are no cabinet openings through
which an adult or child niight be able to insert their
fingers and contact a hazardous voltage. Such open-
ings include, but are not limited to, (1) spacing be-
tween the picture tube and cabinet mask, (2) exces-
sively wide cabinet ventilation
slots, and (3) an
improperly fitted and/or incorrectly secured cabinet
back cover.
c. Antenna Cold Check - With the instrument AC plug
removed from any AC source, connect an electrical
jumper across the two AC plug prongs. Place the in-
strument AC switch in the on position. Connect one
lead of an ohmmeter
to the AC plug prongs tied
together and touch the other ommeter lead in turn
to each tuner antenna input exposed terminal screw
and, if applicable, to the coaxial connector. If the
measured resistance is less than 1.0 megohms or
greater than 5.2 megohms, an abnormality exists that
must be corrected before the instrument is returned
to the customer. Repeat this test with the instrument
AC switch in the off position.
d. Leakage Current Hot Check - With the instrument
completely
reassembled,
plug the AC line cord
directly into a 120V AC outlet. (Do not use an isola-
tion transformer during this test.) Use a leakage cur-
rent tester or a metering system that complies with
American National Standards Institute (ANSI) C101.0
Leakage Current for Appliances and Underwriters
Laboratories (UL) 1410, (50.7). With the instrument AC
switch first in the on position and then in the off posi-
tion, measure from a known earth ground (metal
waterpipe, conduit, etc.) to all exposed metal parts
of the instrument (antennas, handle bracket, metal
cabinet, screwheads, metallic overlays, control shafts,
etc.), especially any exposed metal parts that offer
an electrical return path to the chassis. Any current
measured must not exceed 0.5 milliamps. Reverse
the instrument power cord plug in the outlet and
repeat test.
-2-
LEAKAGE
CURRENT
DEVICE
TESTER
UNDER
L
I
~r;;;:::~~;
(Using
AC adapter
plug as required)
AC Leakage Test
ANY MEASUREMENTS NOT WITHIN THE LIMITS
SPECIFIED
HEREIN
INDICATE
A POTENTIAL
SHOCK HAZARD THAT MUST BE ELIMINATED
BEFORE RETURNING THE INSTRUMENT TO THE
CUSTOMER
OR BEFORE CONNECTING
THE
ANTENNA OR ACCESSORIES.
High Voltage -This
receiver is provided with a hold
down circuit for clearly indicating that voltage has in-
creased in excess of a predetermined
value. Comp-
ly with all notes described in this Service Manual
regarding this hold down circuit when servicing, so
that this hold down circuit may correctly be operated.
Serviceman Warning - With minimum contrast and
brightness, operating high voltage in this receiver is
lower than 31.6kV. In case any component
having
influenced on high voltage is replaced, confirm that
high voltage with minimum contrast and brightness
is lower than 31.6kV.
To measure H.V. use a high impedance
H.V. meter.
Connect (-) to chassis earth and (+) to the CRT
anode
button.
(See the
following
connection
diagram.)
Note: Turn power switch off without fail before the
connection to the anode button is made.
ct
Deflection
PW.B.
High Impedance
I
H.V. meter
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