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leakage current tester (Simpson Model 229 or equivalent) may be
used to make the hot checks, leakage current must not exceed 1/2
milliamp. In case a measurement is outside of the limits specified,
there is a possibility of a shock hazard, and the equipment should
be repaired and rechecked before it is returned to the customer.
3. Prevention of Electro Static Discharge (ESD) to
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 electro static discharge (ESD).
1. Immediately before handling any semiconductor component or
semiconductor-equipped assembly, drain off any ESD on your
body by touching a known earth ground. Alternatively, obtain and
wear a commercially available discharging ESD wrist strap, which
should be removed for potential 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 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 solder removal device. Some solder
removal devices not classified as "anti-static (ESD protected)"
can generate electrical charge 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
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