MAINTENANCE & SERVICE GUIDE
for Prosignia 150 Series Computer
Index Page Preface -or- Notice Specifications Battery Pack
Product Description Illustrated Parts Catalog Troubleshooting Removal & Replacement
Electrostatic DischargeA 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 StaticThe table shows how different activities generate static electricity and at different
electrostatic voltage levels.
Typical Electrostatic Voltages
Event Relative Humidity
10% 40% 55%
Walking across
carpet 35,000 V 15,000
V7,500 V
Walking across vinyl
floor 12,000 V 5,000
V3,000 V
Motions of bench
worker 6,000 V 800 V 400 V
Removing DIPS from
plastic tubes 2,000 V 700 V 400 V
Removing DIPS from
vinyl trays 11,500 V 4,000
V2,000 V
Removing DIPS from
Styrofoam 14,500 V 5,000
V3,500 V
Removing bubble
pack from PCBs 26,000 V 20,000
V7,000 V
Packing PCBs in
foam-lined box 21,000 V 11,000
V5,000 V
NOTE: 700 volts can degrade a product.
Continue Preliminary pages:
Service Considerations
Cables & Connectors
Preparing Computer for Disassembly
Revised: September 16, 1999