Dell 2355DN Service Manual - Page 9

Precautions 1.3 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. Caution >>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 conductive surface, such as aluminum 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 conductive foam, aluminum 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. 1.4 Super Capacitor or Lithium Battery Precautions 1. Exercise caution when replacing a super capacitor or Lithium battery. There could be a danger of explosion and subsequent operator injury and/or equipment damage if incorrectly installed. 2. Be sure to replace the battery with the same or equivalent type recommended by the manufacturer. 3. Super capacitor or Lithium batteries contain toxic substances and should not be opened, crushed, or burned for disposal. 4. Dispose of used batteries according to the manufacture's instructions. 1-5 Service Manual