Chapter 2. Preparing the Computer for Service

Introduction

This chapter provides general service information necessary to prepare the computer for service in the following areas:

o Electrostatic discharge

o Service preliminaries

o Battery disposal

Adherence to the procedures and precautions described in this chapter is essential for proper service.

Chapter 2.1 Electrostatic Discharge

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Static electricity can damage electronic components. Before beginning these procedures, make sure you are grounded (discharged of static electricity) by briefly touching a grounded, unpainted, metal object or surface.

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A sudden discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or micro circuitry. 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. Or 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.

This section details methods of generating, preventing, and grounding static electricity.

Generating Static

Table 2-1 shows how different activities generate static electricity and at different electrostatic voltage levels.

Table 2-1. Typical Electrostatic Voltages

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Relative Humidity

 

Event

10%

40%

55%

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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