Hitachi C43-FD8000, Service Manual

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3
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
defective and/or have been deleted during servicing.
(1) Protective shields are provided on this chassis to
protect both the technician and the customer.
Correctly replace all missing protective shields,
including any removal for servicing convenience.
(2) When reinstalling 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 control knobs, insulating fish-paper,
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. Service technician who
disregard 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 might be able to insert their
fingers and contact a hazardous voltage. Such
openings include, but are not limited to
(1) spacing between the picture tube and cabinet
mask,
(2) excessively 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
source, connect an electrical jumper across the two
AC plug prongs. Place the instrument AC switch in
the ON position. Connect one lead of an ammeter to
the AC plug prongs tied together and touch the other
ohmmeter lead to each tuner antenna input,
exposed terminal screw and, if applicable, to the
coaxial connector in sequence. If the measured
resistance is less than 4.0 megohm or greater than
7.2 megohm, 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 220V outlet. (Do not use an isolation
transformer during this test.) Use a leakage current
tester or a metering system with the instrument AC
switch first in the ON position and then in the OFF
position, measure from a known earth ground (metal
water-pipe, conduit, etc.), to all exposed metal parts
of the instrument (antennas, handle bracket, metal
cabinet, screw heads, 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 0.7 milliamps.
Reverse the instrument power cord plug in the outlet
and repeat test. (See the following connection
diagram)
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
e) High Voltage - This receiver is provided with a hold
down clearly indicating that voltage has increased in
excess of a predetermined value. Comply 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.
f)
Service Warning - With maximum contrast,
operating high voltage in this receiver is lower than
32kV. In case if any component having influence on
high voltage is replaced, confirm that the high
voltage with maximum contrast is lower than 32kV.
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: Must turn power switch off before the connection
to the anode button is made.
(TH01)
INSTRUMENT
UNDER TEST