Removal and Replacement Preliminaries

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 4-1

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 volts.

Maintenance and Service Guide

4–7

Page 118
Image 118
Compaq N800v, EVO M800w, EVO M800c, EVO M80v, N800C Typical Electrostatic Voltage Levels, Relative Humidity Event 10% 40% 55%