Compaq 1200US Presario 1245 Series Maintenance and Service Guide - Page 28

Maintenance & Service Guide Presario 1200 Series Model: 1245 | Home Page | Notice | Preface | Product Description | Troubleshooting Illustrated Parts Catalog | Removal & Replacement Procedures | Specifications Pin Assignments | Battery Pack Operations Electrostatic Discharge A sudden discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or microcircuitry. q Often the spark is neither felt nor heard, but damage occurs. An electronic device exposed to an electrostatic discharge (ESD) may not be affected at all and will work perfectly throughout a normal cycle. Although it may function normally for a while, it is possible for the exposed device's internal layers to degrade, reducing its life expectancy considerably. q Networks built into multiple integrated circuits provide some protection, but in many cases, the discharge can contain enough power to alter device parameters and melt silicon junctions. Generating Static This table shows the different electrostatic voltage levels generated by various activities. NOTE: 700 volts can degrade a product. Typical Electrostatic Voltages Relative Humidity Event Walking across carpet Walking across vinyl floor Motions of bench worker Removing DIPS from plastic tubes Removing DIPS from vinyl trays Removing DIPS from Styrofoam Removing bubble pack from PCBs Packing PCBs in foam-lined box 10% 35,000 V 12,000 V 6,000 V 2,000 V 11,500 V 14,500 V 26,000 V 21,000 V 40% 15,000 V 5,000 V 800 V 700 V 4,000 V 5,000 V 20,000 V 11,000 V 55% 7,500 V 3,000 V 400 V 400 V 2,000 V 3,500 V 7,000 V 5,000 V Return to Removal & Replacement Procedures