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ENGLISH
SAFETY PRECAUTIONS
WARNING: The following precautions must be observed.
ALL PRODUCTS
Before any service is performed on the chassis an
isolation transformer should be inserted between the
power line and the product.
1. When replacing the chassis in the cabinet, ensure
all the protective devices are put back in place.
2. When service is required, observe the original
lead dressing. Extra precaution should be taken to
ensure correct lead dressing in any high voltage
circuitry area.
3. Many electrical and mechanical parts in
HITACHI products 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
on the schematics and the replacement parts
list.
The use of a substitute replacement component
that does not have the same safety characteristics
as the HITACHI recommended replacement one,
shown in the parts list, may create electrical
shock, fire, X-radiation, or other hazards.
4. Always replace original spacers and maintain lead
lengths. Furthermore, where a short circuit has
occurred, replace those components that indicate
evidence of overheating.
5. Insulation resistance should not be less than 2M
ohms at 500V DC between the main poles and
any accessible metal parts.
6. 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.
7. Before returning a serviced product 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. The
service technician must make sure that no
protective device built into the instrument by the
manufacturer has become defective, or
inadvertently damaged during servicing.
CE MARK
1. HITACHI products may contain the CE mark on
the rating plate indicating that the product
contains parts that have been specifically
approved to provide electromagnetic
compatibility to designated levels.
2. When replacing any part in this product, please
use only the correct part itemised in the parts list
to ensure this standard is maintained, and take
care to replace lead dressing to its original state,
as this can have a bearing on the electromagnetic
radiation/immunity.
PICTURE TUBE
1. The line output stage can develop voltages in
excess of 25kV; 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
picture tube.
2. 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 (except for projection
Televisions).
3. The primary source of X-radiation in the product
is the picture tube. The picture 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
4. Keep the picture tube away from the body while
handling. Do not install, remove, or handle the
picture tube in any manner unless shatterproof
goggles are worn. People not so equipped should
be kept away while picture tubes are handled
LASERS
If the product contains a laser avoid direct exposure to
the beam when the cover is open or when interlocks are
defeated or have failed.
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WARNING
Check that exposed parts are acceptably insulated from the supply circuit before returning the repaired
instrument to the customer.
CHECKING METHOD
Measure the resistance value between the both poles of
attachment cup (power supply plug) and the exposed
parts (parts such as covers etc. where the customer can
easily touch) and check that the resistance value is
500k ohms or more.
SAFETY PRECAUTIONS
The following precautions should be observed when servicing.
Since many parts in the unit have special safety related characteristics, always use genuine HITACHI
replacement parts. Especially critical parts in the power circuit block should not be replaced with other makers.
Critical parts are marked with a in the circuit diagram and printed wiring board.
Before returning a repaired unit to the customer, the service technician must thoroughly test the unit to
ascertain that it is completely safe to operate without danger of electrical shock.