Compaq 1500 Personal Computer User Manual


 
Removal and Replacement Preliminaries
Maintenance and Service Guide 4–7
Nonconductive plastic bags, tubes, or boxes
Metal tote boxes
Electrostatic voltage levels and protective materials
Table 4-1 shows how humidity affects the electrostatic voltage
levels generated by different activities.
Table 4-2 lists the shielding protection provided by antistatic bags
and floor mats.
Table 4-1
Typical Electrostatic Voltage Levels
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 tube 2,000 V 700 V 400 V
Removing DIPS from vinyl tray 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 PCB 26,500 V 20,000 V 7,000 V
Packing PCBs in foam-lined box 21,000 V 11,000 V 5,000 V
A product can be degraded by as little as 700 V.
Table 4-2
Static-Shielding Materials
Material Use Voltage Protection Level
Antistatic plastic Bags 1,500 V
Carbon-loaded plastic Floor mats 7,500 V
Metallized laminate Floor mats 5,000 V