D-6
'HOO3UHFLVLRQ'HVNWRS6\VWHPV8VHU©V*XLGH
&RUURVLRQ
The oil from a perso n ’s fingers or prolonged e xpos ure to high tempera ture or hu midity
can corrode the gold-plated edge connectors and pin connectors on various devices in
the computer. This corrosion on computer connectors is a gradual process that can
eventually lead to intermittent failures of electrical circuits.
To prevent corrosion, you should avoid touching contacts on boards and cards. Pro-
tecting th e s ystem from corros ive elements is e speci al ly imp ortant in moist a nd sa lty
environments, which tend to promote corrosion. Also, as a further deterrent to corro-
sion, the system should not be used in extreme temperatures, as explained in
“Temperature” found earlier in this appendix.
(6'
ESD res ults from the build up of s tatic electr icity on the human body and ce rtain other
objects. This static electricity is often produced by simple movements such as walk-
ing acro ss a c arpet. E SD is a discharge of a static el ectric al charge that o ccurs when a
person whose body contains such a charge touches a component in the computer.
This static discharge can cause components, especially chips, to fail. ESD is a prob-
lem particularly in dry environments where the relative humidity is below 50 percent.
To reduce the effects of ESD, you should observe the following guidelines:
When working inside the computer, wear a wrist grounding strap. If a wrist
grounding strap is unavailable, touch an unpainted metal surface on the chassis
periodically to neutralize any static charg e.
If at all possible, stand on a concrete floor while working inside the computer.
Use an antistatic floor mat when working inside the computer.
If it is necessary to work in a carpeted area, sp ray the carpet with an antistatic
spray and allow it to dry before beginning to work inside the computer.
Keep components in t heir antis tatic packagin g until they are installed.
Avoid wearing clothing made of wool or synthetic materials.
(OHFWURPDJQHWLFDQG5DGLR)UHTXHQF\,QWHUIHUHQFH
Electromagnetic interference (EMI) and radio frequency interference (RFI) from a
computer can adversely affect devices such as radio and television (TV) receivers
operating near the computer. Radio frequencies emanating from a computer system
can also interfere with cordless and low -power telephones. Conversely, RFI from high-
power telephones can cause spurious characters to appear on the system’s monitor
screen.
RFI is d efin ed as a ny EMI wi th a fre que nc y above 10 kiloh ertz (kHz). This type of inte r-
ference can travel from the computer to other devices through the AC power cable
and power sou rce or through the air like tr ansmitted radio waves. The Federal Com-
munications Commission (FCC) publishes specific regulations to limit the amount of
EMI and RFI emitted by computing equipment. Each Dell system meets these FCC
regulations.
23186bk0.bk Page 6 Thursday, October 29, 1998 11:07 AM