HP Presario CQ57-200 Compaq Presario CQ57 Notebook PC - Maintenance and Servic - Page 38

CAUTION, If you remove a component, place it in an electrostatic-safe container.

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CAUTION: To prevent damage to the computer when you are removing or installing internal components, observe these precautions: Keep components in their electrostatic-safe containers until you are ready to install them. Before touching an electronic component, discharge static electricity by using the guidelines described in this section. Avoid touching pins, leads, and circuitry. Handle electronic components as little as possible. If you remove a component, place it in an electrostatic-safe container. The following table shows how humidity affects the electrostatic voltage levels generated by different activities. CAUTION: A product can be degraded by as little as 700 V. Event Walking across carpet Walking across vinyl floor Motions of bench worker Removing DIPS from plastic tube Removing DIPS from vinyl tray Removing DIPS from Styrofoam Removing bubble pack from PCB Packing PCBs in foam-lined box Typical electrostatic voltage levels Relative humidity 10% 40% 35,000 V 15,000 V 12,000 V 5,000 V 6,000 V 800 V 2,000 V 700 V 11,500 V 4,000 V 14,500 V 5,000 V 26,500 V 20,000 V 21,000 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 30 Chapter 4 Removal and replacement procedures

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CAUTION:
To prevent damage to the computer when you are removing or installing internal
components, observe these precautions:
Keep components in their electrostatic-safe containers until you are ready to install them.
Before touching an electronic component, discharge static electricity by using the guidelines described
in this section.
Avoid touching pins, leads, and circuitry. Handle electronic components as little as possible.
If you remove a component, place it in an electrostatic-safe container.
The following table shows how humidity affects the electrostatic voltage levels generated by
different activities.
CAUTION:
A product can be degraded by as little as 700 V.
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
30
Chapter 4
Removal and replacement procedures