HP Pro 3380 Spécifications télécharger pdf (Page 45)

6 Routine Care and Disassembly

Preparation

This chapter provides general service information for the computer. Adherence to the procedures and

precautions described in this chapter is essential for proper service.

CAUTION: When the computer is plugged into an AC power source, voltage is always applied to

the system board. You must disconnect the power cord from the power source before opening the

computer to prevent system board or component damage.

Electrostatic Discharge Information

A sudden discharge of static electricity from your 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 appear to be affected at all and can work

perfectly throughout a normal cycle. The device may function normally for a while, but it has been

degraded 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 following table shows that:

●

Different activities generate different amounts of static electricity.

●

Static electricity increases as humidity decreases.

Relative Humidity

Event 55% 40% 10%

Walking across carpet

Walking across vinyl floor

Motions of bench worker

Removing DIPs* from plastic tube

7,500 V

3,000 V

400 V

15,000 V

5,000 V

800 V

700 V

35,000 V

12,000 V

6,000 V

2,000 V

Electrostatic Discharge Information 35

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HP Pro 3380 Spécifications Page 45