Xerox 3400N Service Guide - Page 8

ESD Precautions Some semiconductor devices are easily damaged from static electricity. These components are Electrostatically Sensitive Devices (ESDs); examples include integrated circuits (ICs), Large-Scale Integrated circuits (LSIs), some field-effect transistors and semiconductor chip components. The following techniques will reduce the occurrence of component damage caused by static electricity: Caution: Be sure the power is off to the chassis or circuit board, and observe all other safety precautions. I Immediately before handling any semiconductor components assemblies, drain the electrostatic charge from your body by touching a known earth ground. Alternatively, wear a discharging wrist strap device. (Be sure to remove the strap before applying power to the unit under test to avoid potential shock.) I After removing an ESD-equipped assembly, place it on a conductive surface such as aluminum foil to prevent accumulation of an electrostatic charge. I Do not use freon-propelled chemicals. These can generate electrical charges sufficient to damage ESDs. I Use only a ground-tip soldering iron when soldering or desoldering ESDs. I Use only an anti-static solder removal device. Some solder removal devices are not rated as "anti-static"; these can accumulate a sufficient electrical charge to damage ESDs. I Do not remove a replacement ESD from its protective package until you are ready to install it. Most replacement ESDs are packaged with leads that are electrically shorted together by conductive foam, aluminum foil or other conductive materials. I Immediately before removing the protective 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. I Minimize body motions when handling unpackaged replacement ESDs. Motion such as your clothes brushing together, or lifting a foot from a carpeted floor can generate enough static electricity to damage an ESD. I Handle ICs and EPROMs carefully to avoid bending a pin. I Pay attention to the direction of parts when mounting or inserting them on a PCB. I Components can be permanently damaged if heated for longer than necessary while soldering. All components are susceptible to heat damage.