AT&T Map/40, Руководство пользователя

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Getting Started
1-3
Avoiding Electrostatic Discharge
Damage
The human body can collect thousands of volts of destructive static electricity
from ordinary activities, for example, walking on a rug, handling synthetic materi-
als, or wearing synthetic clothes. When this static electricity discharges onto
another surface at a different voltage potential, it is called
electrostatic discharge
or
ESD
.
A person cannot feel ESD below approximately 3500 volts. However, only 30 volts
is needed to damage ESD-sensitive electronic components.
Circuit cards and packaging materials that contain ESD-sensitive components are
often marked with a yellow and black warning symbol. Proper grounding tech-
niques prevent the discharge of damaging static electricity from your body into
these ESD-sensitive components during handling.
There is no quick method of testing for ESD damage. Components that are dam-
aged may simply fail after a brief period of normal operation.
To avoid damaging ESD-sensitive components, follow these rules:
■
Handle ESD-sensitive circuit cards only after you have attached a wrist
strap to the bare skin of your wrist. Attach the other end of the wrist strap to
a ground that terminates at the system ground, such as any unpainted
metallic chassis surface.
■
Handle a circuit card by the faceplate or side edges only. Do
not
touch
components, leads, or connector areas (gold finger pins).
■
Hold a short circuit card by the faceplate only. See Figure 1-1.
■
Hold a larger circuit card as shown in Figure 1-2. Ensure palm is not in con-
tact with the board wiring side.
■
Keep circuit cards away from plastics and other synthetic materials such as
polyester clothing.
■
Do
not
hand circuit cards to another person unless that person is grounded
at the same potential level.
■
Hold devices such as a hard disk, floppy drive, or cartridge tape drive as
you would a large circuit card. The ESD sensitive area of these compo-
nents is located on the bottom surface. Hold these drives on the areas rec-
ommended below.