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SAFETY PRECAUTIONS
WARNING:
The following
precautions
should
be
observed .
1.
Do not instail, remove, or handle the picture tube
in any manner unless shatter proof goggles are
worn. People not so equipped should be kept
away while picture tubes are handled. Keep the
picture tube away from the body while handling.
2. When service is required, an isolation transformer
should be inserted between the power line and
the receiver before any service is performed on
the chassis.
3.
When replacing the chassis in the cabinet, ensure
all the protective devices are put back in place.
4,
When
service is required, observe the original
lead dressing. Extra precaution should be taken
to ensure
correct
lead
dressing
in the high
voltage circuitry area.
5. Always
use
the
manufacturer's
replacement
component. Always replace original spacers and
maintain
lead
lengths.
Especially
critical
components are indicated thus A on the parts
list and should not be replaced by other makes.
Furthermore, where a short circuit has occurred,
replace those components that indicate evidence
of overheating.
6.
Before
returning
a serviced
receiver
to the
customer, the service technician must thoroughly
test the unit to be certain that it is completely safe
to operate without danger of electrical shock, and
be sure that no protective device built into the
instrument
by the manufacturer
has
become
defective,
or
inadvertently
damaged
during
servicing.
Therefore, the following checks are recommended for
the continued
protection
of the customers
and
service technicians.
INSULATION
Insulation resistance should not be less than 10M
ohms at 500V DC between the main poles and any
accessible metal parts.
Also, no flashover or breakdown should occur during
the dielectric
strength
test, applying
3kV AC
or
4.25kV DC for two seconds between the main poles
and accessible metal parts.
HIGH VOLTAGE
High voltage should always be kept at the rated value
of the chassis and no higher. Operating at higher
voltages may cause a failure of the picture tube or
high
voltage
supply,
and
also,
under
certain
circumstances
could
produce
X-radiation
levels
moderately
in excess
of design
levels.
The
high
voltage must not, under any circumstances,
exceed
29kV on the chassis.
X-RADIATION
TUBES:
The primary source of X-radiation
in this
receiver is the picture tube. The tube utilised for the
above mentioned function in this chassis is specially
constructed to limit X-radiation.
For continued X-radiation
protection, replace tube
with the same type as the original HITACHI approved
type.
PRODUCT SAFETY NOTICE
Many electrical and mechanical
parts in HITACHI
television
receivers
have
special
safety
related
characteristics. These characteristics are often not
evident from visual inspection, nor can the protection
afforded by them necessarily be obtained by using
replacement components
rated for higher voltage,
wattage, etc. Replacement parts which have these
special
safety
characteristics
are
identified
by
marking with a A on the schematics
and the
replacement
parts
list contained
in this service
manual.
The
use
of a substitute
replacement
component
which does not have the same safety characteristics
as the HITACHI
recommended
replacement
one,
shown
in the parts list of this service manual, may
create
electrical
shock,
fire, X-radiation,
or other
hazards.
Product Safety is continuously under review, and new
instructions are issued from time to time. For the
latest
information,
always
consult
the
current
HITACHI
service
manual.
A subscription
to, or
additional copies of HITACHI service manuals may be
obtained at a nominal
charge from your HITACHI
SALES CORPORATION.
CE MARK
Some of these models may contain the CE mark on
the rating plate.
This illustrates that the T.V. contains parts that have
been
specifically
approved
to
provide
electromagnetic compatability to designated levels.
Therefore, when replacing any part in this T.V., please
use only the correct part itemized in the parts list of
this service
manual
to ensure
this
standard
is
maintained.
Also, take care to replace lead dressing to its original
state,
as this can
also
have
a bearing
on
the
electromagnetic radiation/immunity.
TUBE DISCHARGE
The line output stage can develop voltages in excess
of 25k\V; if the E.H.T. cap is required to be removed,
discharge the anode
to chassis via a high value
resistor, prior to its removal from the tube.
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