Compaq.com - Compaq Presario 1900 Series Maintenance and Service Guide - Models: 1905, 1906, 1910, 1915, 1919, and 1920
United States June 27, 2004
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Maintenance & Service Guide
Presario 1900 Series
Models: 1905, 1906, 1910, 1915, 1919, 1920, 1922, and 1925
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Removal & Replacement Procedures
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Electrostatic Discharge
A sudden discharge of static electricity from a finger or other conductor can destroy static-
sensitive devices or microcircuitry. Often the spark is neither felt nor heard, but damage
occurs. An electronic device exposed to 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, then degrade 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 shows how different activities generate static electricity and at different
electrostatic voltage levels.
Typical Electrostatic Voltages
Relative Humidity
Event
10%
40%
55%
Walking across carpet
35,000 V
15,000 V
7,500 V
Walking across vinyl floor
12,000 V
5,000 V
3,000 V
Motions of bench worker
6,000 V
800 V
400 V
Removing DIPS from plastic tubes
2,000 V
700 V
400 V
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