Cleaning Drives; Environmental Factors; Temperature; Humidity - Dell Precision 400 User Manual

4. Use the moistened cloth to wipe the computer
cover, the keyboard, and the exterior of the moni-
tor(s), including the screen.

Cleaning Drives

You can clean the heads of your diskette drives by using a
commercially available diskette-drive head-cleaning kit.
These kits include diskettes pretreated with a chemical
solution to nonabrasively remove contaminants that
accumulate on the drive heads during normal operation.
If the kit does not contain instructions, insert one of the
pretreated diskettes into a diskette drive and turn on the
system. After 20 or 30 seconds, remove the diskette from
the drive. Repeat this procedure for each diskette drive in
the computer.
CAUTION: Do not attempt to clean drive heads
with a swab. You may accidentally misalign the
heads, rendering the drive inoperable.
E
nvironmental Factors
This section discusses various environmental factors that
can adversely affect system performance and longevity.

Temperature

Temperature extremes can cause a variety of problems,
including premature aging and failure of chips or
mechanical failure of devices. Extreme temperature fluc-
tuations can cause chips to become loose in their sockets
and can cause expansion and contraction of disk drive
platters, resulting in read or write data errors. When you
perform a low-level format operation on a hard-disk
drive, it is important to ensure that the drive's surround-
ing temperature is at or near the temperature at which the
drive will be operated. Failure to do so can result in relo-
cation of the tracks on the disk platters.
To minimize the negative effects of temperature on sys-
tem performance, follow these guidelines:
•
Ensure that the system is operated in an environment
no colder than 10 Celsius (C) (50 Fahrenheit [F])
or hotter than 35 C (95 F).
•
Ensure that the system has adequate ventilation. Do
not place it within a closed-in wall unit or on top of
cloth material, which can act as insulation. Do not
place it where it will receive direct sunlight, particu-
larly in the afternoon. Do not place it next to a heat
source of any kind, including heating vents during
winter.
Adequate ventilation is particularly important at high
altitudes. System performance may not be optimum
when the system is operating at high temperatures as
well as high altitudes.
•
Make sure that all slots and openings on the com-
puter remain unobstructed, especially the fan vent on
the back of the computer.
•
Clean the system at regular intervals to avoid any
buildup of dust and debris, which can cause a system
to overheat.
•
If the system has been exposed to abnormally cold
temperatures, allow a two-hour warm-up period to
bring it up to normal operating temperature before
turning it on. Failure to do so may cause damage to
internal components, particularly the hard-disk
drive.
•
If intermittent system failures are noticed, try reseat-
ing any socketed chips, which might have become
loose due to temperature fluctuations.

Humidity

High-humidity conditions can cause moisture migration
and penetration into the computer. This moisture can
cause corrosion of internal components and degradation
of properties such as electrical resistance, thermal con-
ductivity, physical strength, and size. Extreme moisture
buildup inside the computer can result in electrical shorts,
which can cause serious damage to the computer.
Each Dell system is rated to operate at 20 to 80 percent
relative humidity, with a humidity gradation of 10 per-
cent per hour. In storage, a Dell system can withstand
from 5 to 95 percent relative humidity.
Buildings in which climate is controlled by air-
conditioning in the warmer months and by heat during
the colder months usually maintain an acceptable level of
humidity for computer equipment. However, if a system
is located in an unusually humid location, a dehumidifier
Maintaining the System D-3