HP 255 G4, Руководство по техническому обслуживанию и ремонту

Страница: 32 / 108

Drive handling
CAUTION: Drives are fragile components that must be handled with care. To prevent damage to the
computer, damage to a drive, or loss of information, observe these precautions:
Before removing or inserting a hard drive, shut down the computer. If you are unsure whether the computer
is off or in Hibernation, turn the computer on, and then shut it down through the operating system.
Before handling a drive, be sure that you are discharged of static electricity. While handling a drive, avoid
touching the connector.
Before removing a diskette drive or optical drive, be sure that a diskette or disc is not in the drive and be sure
that the optical drive tray is closed.
Handle drives on surfaces covered with at least one inch of shock-proof foam.
Avoid dropping drives from any height onto any surface.
After removing a hard drive, an optical drive, or a diskette drive, place it in a static-proof bag.
Avoid exposing an internal hard drive to products that have magnetic fields, such as monitors or speakers.
Avoid exposing a drive to temperature extremes or liquids.
If a drive must be mailed, place the drive in a bubble pack mailer or other suitable form of protective
packaging and label the package “FRAGILE.”
Grounding guidelines
Electrostatic discharge damage
Electronic components are sensitive to electrostatic discharge (ESD). Circuitry design and structure
determine the degree of sensitivity. Networks built into many integrated circuits provide some protection,
but in many cases, ESD contains enough power to alter device parameters or melt silicon junctions.
A discharge of static electricity from a finger or other conductor can destroy static-sensitive devices or
microcircuitry. Even if the spark is neither felt nor heard, damage may have occurred.
An electronic device exposed to ESD may not be affected at all and can work perfectly throughout a normal
cycle. Or the device may function normally for a while, then degrade in the internal layers, reducing its life
expectancy.
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.
24 Chapter 4 Removal and replacement procedures preliminary requirements