Hitachi 42V710 - 42" Rear Projection TV, Service Manual

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4
LC48/B-LC47/B/K
CAUTION:
Before servicing instruments covered by this service
data and its supplements and addenda, read and follow the SAFE-
TY PRECAUTIONS on page 2 of this publication.
NOTE: If unforseen circumstances create conflict between the fol-
lowing SERVICING PRECAUTIONS and any of the SAFETY PRE-
CAUTIONS on page 2 of this publication, always follow the SAFETY
PRECAUTIONS.
Remember: Safety First.
General Servicing Guidelines
1.
Always unplug the instrument AC power cord from the AC power
source before:
a.
Removing or reinstalling any component, circuit board,
module, or any other instrument assembly.
b. Disconnecting or reconnecting any instrument electrical
plug or other electrical connection.
c. Connecting a test substitute in parallel with an electrolyt-
ic capacitor in the instrument.
CAUTION: A wrong part substitution or incorrect
polarity installation of electrolytic
capacitors may result in an
explosion hazard.
2. Do not spray chemicals on or near this instrument or any of its
assemblies.
3. Unless specified otherwise in these service data, clean electri-
cal contacts by applying the following mixture to the contacts
with a pipe cleaner, cotton-tipped stick or comparable nonabra-
sive applicator: 10% (by volume) Acetone and 90% (by volume)
ispropyle alchohol (90%-99% strength).
CAUTION: This is a flammable mixture. Unless specified
otherwise in these service data, lubrication of
contacts is not required.
4. Do not defeat any plug/socket B+ voltage interlocks with which
instruments covered by this service data might be equipped.
5. Do not apply AC power to this instrument and/or any of its elec-
trical assemblies unless all solid-state device heat-sinks are cor-
rectly installed.
6. Always connect the test instrument ground lead to the appropri-
ate instrument chassis ground before connecting the test instru-
ment positive lead. Always remove the test instrument ground
lead last.
7. Use with this instrument only the test fixtures specified in this
service data.
CAUTION: Do not connect the test fixture ground strap to
any heatsink in this instrument.
Electrostatically Sensitive (ES) Devices
Some semiconductor (solid state) devices can be damaged easily by
static electricity.
Such components commonly are called
Electrostatically Sensitive (ES) Devices. Examples of typical ES
devices are integrated circuits and some field-effect transistors and
semiconductor “chip” components. The following techniques should
be used to help reduce the incidence of component damage caused
by static electricity.
1. Immediately before handling any semiconductor component or
semiconductor-equipped assembly, drain off any electrostatic
charge on your body by touching a known earth ground.
Alternatively, obtain and wear a commercially available dis-
charging wrist strap device, which should be removed for poten-
tial shock reasons prior to applying power to the unit under test.
2. After removing an electrical assembly equipped with ES
devices, place the assembly on a conductive surface such as
aluminum foil, to prevent electrostatic charge build-up or expo-
sure of the assembly.
3. Use only a grounded-tip soldering iron to solder or desolder ES
devices.
4. Use only an anti-static type solder removal device. Some solder
removal devices not classified as “anti-static” can generate elec-
trical charges sufficient to damage ES device.
5. Do not use freon-propelled chemicals. These can generate
electrical charges sufficient to damage ES devices.
6. Do not remove a replacement ES device from its protective
package until immediately before you are ready to install it.
(Most replacement ES devices are packaged with leads electri-
cally shorted together by conductive foam, aluminum foil or com-
parable conductive material.)
7. Immediately before removing the protective material from the
leads of a replacement ES device, touch the protective material
to the chassis or circuit assembly into which the device will be
installed.
CAUTION: Be sure no power is applied to the chassis or
circuit, and observe all other safety precautions.
8. Minimize bodily motions when handling unpackaged replace-
ment ES devices.
(Otherwise harmless motion such as the
brushing together of your clothes fabric or the lifting of your foot
from a carpeted floor can generate static electricity sufficient to
damage an ES device.)
SERVICING PRECAUTIONS
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