Hitachi DV-PF33U, Service Manual

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1-2
1-2 IMPORTANT SAFETY PRECAUTIONS
1-2-1 Product Safety Notice
Some electrical and mechanical parts have special
safety-related characteristics which are often not evi-
dent from visual inspection, nor can the protection they
give necessarily be obtained by replacing them with
components rated for higher voltage, wattage, etc.
Parts that have special safety characteristics are iden-
tified by a
#
on schematics and in parts lists. Use of a
substitute replacement that does not have the same
safety characteristics as the recommended replace-
ment part might create shock, fire, and/or other haz-
ards. The Product’s Safety is under review
continuously and new instructions are issued when-
ever appropriate. Prior to shipment from the factory,
our products are carefully inspected to confirm with
the recognized product safety and electrical codes of
the countries in which they are to be sold. However, in
order to maintain such compliance, it is equally impor-
tant to implement the following precautions when a set
is being serviced
.
1-2-2 Precautions during Servicing
A. Parts identified by the
#
symbol are critical for
safety. Replace only with part number specified.
B. In addition to safety, other parts and assemblies
are specified for conformance with regulations
applying to spurious radiation. These must also be
replaced only with specified replacements.
Examples: RF converters, RF cables, noise block-
ing capacitors, and noise blocking filters, etc.
C. Use specified internal wiring. Note especially:
1)Wires covered with PVC tubing
2)Double insulated wires
3)High voltage leads
D. Use specified insulating materials for hazardous
live parts. Note especially:
1)Insulation tape
2)PVC tubing
3)Spacers
4)Insulators for transistors
E. When replacing AC primary side components
(transformers, power cord, etc.), wrap ends of
wires securely about the terminals before solder-
ing.
F. Observe that the wires do not contact heat produc-
ing parts (heatsinks, oxide metal film resistors, fus-
ible resistors, etc.).
G. Check that replaced wires do not contact sharp
edges or pointed parts.
H. When a power cord has been replaced, check that
5 - 6 kg of force in any direction will not loosen it.
I. Also check areas surrounding repaired locations.
J. Be careful that foreign objects (screws, solder
droplets, etc.) do not remain inside the set.
K. Crimp type wire connector
The power transformer uses crimp type connectors
which connect the power cord and the primary side
of the transformer. When replacing the transformer,
follow these steps carefully and precisely to prevent
shock hazards.
Replacement procedure
1)Remove the old connector by cutting the wires at a
point close to the connector.
Important: Do not re-use a connector. (Discard it.)
2)Strip about 15 mm of the insulation from the ends
of the wires. If the wires are stranded, twist the
strands to avoid frayed conductors.
3)Align the lengths of the wires to be connected.
Insert the wires fully into the connector.
4)Use a crimping tool to crimp the metal sleeve at its
center. Be sure to crimp fully to the complete clo-
sure of the tool.
L. When connecting or disconnecting the internal
connectors, first, disconnect the AC plug from the
AC outlet.