Compaq 12XL325 Presario 1200 Series Models XL101-XL113, XL115, XL118-XL127 - M - Page 82

Presario 1200 Series Models: XL101-XL113, XL115, XL118-XL127 Electrostatic Discharge A sudden discharge of static electricity from a finger or other conductor can destroy staticsensitive devices or microcircuitry. Often the spark is neither felt nor heard, but damage occurs. An electronic device exposed to electrostatic discharge (ESD) may not seem to be affected at all and works perfectly throughout a normal cycle. Although it may function normally for a while, it may be degraded in the internal layers, reducing its life expectancy. Networks built into many integrated circuits provide some protection, but in many cases, the discharge contains enough power to alter device parameters or melt silicon junctions. Generating Static The table below shows activities that generate static electricity and the associated electrostatic voltage level. Typical Electrostatic Voltages Event Relative Humidity 10% 40% 55% Walking across carpet Walking across vinyl floor Motions of bench worker 35,000 V 12,000 V 6,000 V 15,000 V 5,000 V 800 V 7,500 V 3,000 V 400 V Removing DIPS from plastic tubes 2,000 V 700 V 400 V Removing DIPS from vinyl trays 11,500 V 4,000 V 2,000 V Removing DIPS from styrofoam 14,500 V 5,000 V 3,500 V Removing bubble pack from PCBs 26,000 V Packing PCBs in foam-lined box 21,000 V Note: 700 Volts can degrade a product. 20,000 V 11,000 V 7,000 V 5,000 V 2 REMOVAL SEQUENCE PRESARIO NOTEBOOK MAINTENANCE AND SERVICE GUIDE 1200XL SERIES