Esd Precautions - Xerox Phaser 3435 Service Manual

Introduction

ESD Precautions

Certain semiconductor devices can be easily damaged by static electricity. Such components are
commonly called "Electrostatically Sensitive (ES) Devices", or ESDs. Examples of typical ESDs
are: integrated circuits, some field effect transistors, and semiconductor "chip" components.
The techniques outlined below should be followed to help reduce the incidence of component
damage caused by static electricity.
Be sure no power is applied to the chassis or circuit, and observe all other safety precautions.
1. Immediately before handling a semiconductor component or semiconductor-equipped
assembly, drain off any electrostatic charge on your body by touching a known earth ground.
Alternatively, employ a commercially available wrist strap device, which should be removed
for your personal safety reasons prior to applying power to the unit under test.
2. After removing an electrical assembly equipped with ESDs, place the assembly on a conduc-
tive surface, such as aluminium or copper foil, or conductive foam, to prevent electrostatic
charge buildup in the vicinity of the assembly.
3. Use only a grounded tip soldering iron to solder or desolder ESDs.
4. Use only an "anti-static" solder removal device. Some solder removal devices not classified
as "anti-static" can generate electrical charges sufficient to damage ESDs.
5. Do not use Freon-propelled chemicals. When sprayed, these can generate electrical charges
sufficient to damage ESDs.
6. Do not remove a replacement ESD from its protective packaging until immediately before
installing it. Most replacement ESDs are packaged with all leads shorted together by conduc-
tive foam, aluminium foil, or a comparable conductive material.
7. Immediately before removing the protective shorting material from the leads of a replacement
ESD, touch the protective material to the chassis or circuit assembly into which the device will
be installed.
8. Maintain continuous electrical contact between the ESD and the assembly into which it will be
installed, until completely plugged or soldered into the circuit.
9. Minimize bodily motions when handling unpackaged replacement ESDs. Normal motions,
such as the brushing together of clothing fabric and lifting one's foot from a carpeted floor,
can generate static electricity sufficient to damage an ESD.
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CAUTION
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