PT3-E/G AVC3-U
SERVICING PRECAUTIONS
CAUTION: Before servicing instruments covered by thisElectrostatically Sensitive (ES) Devices
service data and its supplements and addenda, read andSome semiconductor (solid state) devices can be damaged
follow the ?Important Safety Instructions? on page 3 of thiseasily by static electricity. Such components commonly are
publication.called Electrostatically Sensitive (ES) Devices. Examples of
NOTE: If unforeseen circumstances create conflict betweentypical ES devices are integrated circuits and some field-
the following servicing precautions and any of the safetyeffect transistors and semiconductor ?chip? components. The
precautions on page 3 of this publication, always follow thefollowing techniques should be used to help reduce the
safety precautions. Remember: Safety First.incidence of component damage caused by static electricity.
General Servicing Guidelines1. Immediately before handling any semiconductor
1. Always unplug the instrument AC power cord from the ACcomponent or semiconductor-equipped assembly, drain
power source before: off any electrostatic charge on your body by touching a
a. Removing or reinstalling any component, circuitknown earth ground. Alternatively, obtain and wear a
board, module, or any other instrument assembly. commercially available discharging wrist strap device,
which should be removed for potential shock reasons
b. Disconnecting or reconnecting any instrumentprior to applying power to the unit under test.
electrical plug or other electrical connection.
2. After removing an electrical assembly equipped with ES
c. Connecting a test substitute in parallel with andevices, place the assembly on a conductive surface
electrolytic capacitor in the instrument.such as aluminum foil, to prevent electrostatic charge
buildup or exposure of the assembly.
CAUTION: A wrong part substitution or incorrect
polarity installation of electrolytic3. Use only a grounded-tip soldering iron to solder or
capacitors may result in an explosiondesolder ES devices.
hazard.
4. Use only an anti-static type solder removal device. Some
2. Do not spray chemicals on or near this instrument or anysolder removal devices not classified as ?anti-static? can
of its assemblies.generate electrical charges sufficient to damage ES
device.
3. Unless specified otherwise in these service data, clean
electrical contacts by applying the following mixture to the5. Do not use freon-propelled chemicals. These can
contacts with a pipe cleaner, cotton-tipped stick orgenerate electrical charges sufficient to damage ES
comparable nonabrasive applicator: 10% (by volume)devices.
Acetone and 90% (by volume) isopropyl alcohol (90%-
99% strength). 6. Do not remove a replacement ES device from its
CAUTION: This is a flammable mixture. Unlessprotective package until immediately before you are
specified otherwise in these service data,ready to install it. (Most replacement ES devices are
lubrication of contacts is not required.packaged with leads electrically shorted together by
conductive foam, aluminum foil or comparable conductive
4. Do not defeat any plug/socket of voltage interlocks withmaterial.)
which instruments covered by this service data might be
equipped.7. Immediately before removing the protective material from
the leads of a replacement ES device, touch the
5. Do not apply AC power to this instrument and/or any of itsprotective material to the chassis or circuit assembly into
electrical assemblies unless all solid-state device heat-which the device will be installed.
sinks are correctly installed.CAUTION: Be sure no power is applied to the chassis or
circuit, and observe all other safety
6. Always connect the test instrument ground lead to theprecautions.
appropriate instrument chassis ground before connecting
the test instrument positive lead. Always remove the test8. Minimize bodily motions when handling unpackaged
instrument ground lead last.replacement ES devices. (Otherwise harmless motion
such as the brushing together of your clothes fabric or the
7. Use with this instrument only the test fixtures specified inlifting of your foot from a carpeted floor can generate
this service data.static electricity sufficient to damage an ES device.)
CAUTION: Do not connect the test fixture ground strap
to any heatsink in this instrument.
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