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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
discharging wrist strap device, which should be removed to prevent potential shock
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 buildup
or exposure of the assembly.
3. Use only a grounded-tip soldering iron to solder or unsolder ES devices.
4. Use only an anti-static type folder removal device. Some solder removal devices not
classified as “anti-static” can generate electrical charges sufficient to damage ES
devices.
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 electrically shorted together by conductive foam, aluminum foil or comparable
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 replacement ES devices.
(Otherwise even some normally harmless motions such as mutual brushing of your
clothes’ fabric or lifting of your foot from a carpeted floor might generate static electricity
sufficient to damage an ES device.)
General Soldering Guidelines
Use a grounded-tip, low-wattage soldering iron and appropriate tip size and shape that
will maintain tip temperature within the range of 500
o
F to 600
o
F.
Use an appropriate gauge of RMA resin-core solder composed of 60 parts tin/40 parts
lead.
Keep the soldering iron tip clean and well tinned.
Thoroughly clean the surfaces to be soldered. Use a mall wire bristle (0.5 inch, or 1.25cm)
brush with a metal handle. Do not use freon-propelled spay-on cleaners.
Use the following unsoldering technique
a. Allow the soldering iron tip to reach normal temperature. (500
o
F to 600
o
F)
Summary of Contents for HTR20-A
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