Hardware Reference
In-Depth Information
If you do not have such a mat, place the removed circuits and devices on a clean desk or
table. Always pick up a loose adapter card by the metal bracket used to secure the card to
the system. This bracket is tied into the ground circuitry of the card, so by touching the
bracket first, you prevent a discharge from damaging the components of the card. If the
circuit board has no metal bracket (a motherboard, for example), handle the board care-
fully by the edges, and try not to touch any of the connectors or components. If you don't
have proper ESD equipment such as a wrist strap or mat, be sure to periodically touch the
chassis while working inside the system to equalize any charge you might have built up.
Caution
Some people recommend placing loose circuit boards and chips on sheets of aluminum foil.
I absolutely do not recommend this procedure because it can actually result in an explosion!
Many motherboards, adapter cards, and other circuit boards have built-in lithium or NiCad
batteries. These batteries react violently (overheating and possibly exploding) when they are
shorted out, which is exactly what you would be doing by placing such a board on a piece
of aluminum foil. Because you will not always be able to tell whether a board has a battery
builtintoitsomewhere, thesafest practice istoneverplace aboardonanyconductive metal
surface.
Recording Physical Configuration
While you are assembling a system, you should record all the physical settings and con-
figurations of each component, including jumper and switch settings, cable orientations
and placement, ground wire locations, and even adapter board placement. Keep a note-
book handy for recording these items, and write down all the settings. See
Chapter 4
for
moreinformationonmotherboardconnector,jumper,andothercomponentlocations.
Fig-
ure 19.3
shows a typical motherboard jumper.
Figure 19.3
The jumper position shown here is used to configure the motherboard's PCI and USB inter-
face.
