Maintenance and Service Guide

Table Of Contents
Routine care, SATA drive guidelines, and
disassembly preparation
3
This information provides general service information for the computer. Adherence to the procedures and
precautions is essential for proper service.
IMPORTANT: 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
nger 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) might not appear to be aected at all and can
work perfectly throughout a normal cycle. The device might 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.
IMPORTANT: To prevent damage to the device when you are removing or installing internal components,
obser
ve 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.
Generating static electricity
This table shows how humidity aects the electrostatic voltage levels generated by dierent activities. A
product can be degraded by 700 V.
Dierent activities generate dierent amounts of static electricity.
Static electricity increases as humidity decreases.
Table 3-1 Static electricity occurrence based on activity and humidity
Relative humidity
Event 55% 40% 10%
Walking across carpet
Walking across vinyl
oor
7,500 V
3,000 V
15,000 V
5,000 V
35,000 V
12,000 V
Routine care, SATA drive guidelines, and disassembly preparation 11