Servicing Precautions; Size, Position And Tilt Adjustment - Hitachi 36SDX88B Service Manual

SERVICING PRECAUTIONS
CAUTION: Before servicing instruments covered by this service
data
and its supplements and addenda, read and follow the SAFE-
TY PRECAUTIONS on page 3 of this publication.
NOTE: If unforseen circumstances create conflict between the fol-
lowing servicing precautions and any of the safety precautions on
page 3 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.
d. Discharging the picture tube anode.
2. Test high voltage only by measuring it wih an appropriate high
voltage meter or other voltage measuring device (DVM,
FETVOM, etc.) equipped with a suitable high voltage probe. Do
not test high voltage by "drawing an arc."
3. Discharge the picture tube's anode by (a) first connecting one
end
of an insulated clip lead to the degaussing or kine aquadag
grounding system shield at the point where the picture tube
socket ground lead is connected, and then (b) touch the other
end of the insulated clip lead to the picture tube high voltage
output, using an insulated handle to avoid personal contact with
high vottage.
4. Do not spray chemicals on or near this instrument or any of its
assembties.
5. 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 alchohot (90%-99% strength).
CAUTION: This is a flammable mixture. Unless specified
otherwise in these service data, lubrication of
contacts is not required.
6. Do not defeat any plug/socket B+ voltage interlocks with which
instruments covered by this service data might be equipped.
7. 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.
8. Always connect the test instrument ground lead to the appropri-
ate instrument chassis ground before connecting the test instru-
ment positive tead. Always remove the test instrument ground
lead last.
9. 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.
2.
3.
4.
5.
6.
7.
8.
tmmediately 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.
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.
Use only a grounded-tip soldering iron to solder or desolder ES
devices.
Use only an anti-static type solder removal device. Some sol-
der removal devices not classified as "anti-static" can generate
etectrical charges sufficient to damage ES device.
Do not use freon-propelled chemicals. These can generate
electrical charges sufficient to damage ES devices.
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 shot-ted together by conductive foam, aluminum foil or
comparable conductive material.)
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.
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.)
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