Magnetism; Shock And Vibration; Power Source Interruptions - Dell 6100 User Manual

•
Use a directional outdoor TV antenna.
•
Attach line filters to the TV set.
•
Use 75-ohm coaxial cable for the TV set rather than
twin-lead antenna wire.
•
If interference occurs, rotate the computer or the TV
set 90 degrees.

Magnetism

Because they store data magnetically, diskettes and hard-
disk drives are extremely susceptible to the effects of
magnetism. Diskettes should never be stored near mag-
netic sources such as the following:
•
Monitors
•
TV sets
•
Printers
•
Telephones with real bells
•
Fluorescent lights

Shock and Vibration

Excessive shock can damage the function, external
appearance, and physical structure of a system. Each Dell
system has been designed to operate properly after with-
standing a minimum of six consecutively executed shock
pulses in the positive and negative x, y, and z axes. Each
shock pulse can measure up to 5 gravities (G) for up to
11 milliseconds (ms). In storage, the system can with-
stand shock pulses of 20 G with a velocity change of
1397 millimeters (mm) per second (55 inches per
second).
Excessive vibration can cause the same problems as men-
tioned earlier for shock, as well as cause components to
become loose in their sockets or connectors. Systems can
be subject to significant vibration when being transported
by vehicle or when operated in an environment with
machinery that causes vibration.
Each Dell system, when operating, is designed to
withstand 0.25 G (half-sine wave) at a sweep of 3 to
300 hertz (Hz) for 15 minutes. In storage, the system can
withstand 0.5 G at 3 to 300 Hz for 15 minutes.

Power Source Interruptions

Computer systems are especially sensitive to variations
in voltage supplied by the AC power source. Over-
voltage, undervoltage, and transients (or spikes) can erase
data from memory or even cause components to fail. To
protect against these types of problems, power cables
should always be properly grounded and one or both of
the following methods should be used:
•
Use an uninterruptible power supply (UPS) or one of
the other power protection devices described in the
following section, "Power Protection Devices."
•
Place the system on a dedicated power circuit (rather
than sharing a circuit with other heavy electrical
equipment). In general, do not allow the system to
share a circuit with any of the following:
— Kitchen appliances
— Copier machines
— Air conditioners
— Vacuum cleaners
— Space heaters
— Power tools
— Teletype machines
— Adding machines
— Laser printers
— Facsimile machines
— Any other motorized equipment
Besides these appliances, the greatest threat to a system's
supply of power are surges or blackouts caused by elec-
trical storms. Whenever possible, turn off the computer
and any peripherals and unplug them from their power
sources during thunderstorms.
If a blackout occurs—even a temporary one—while the
system is turned on, turn off the system immediately and
disconnect it from its power source. Leaving the system
on may cause problems when the power is restored; all
other appliances left on in the area can create large volt-
age spikes that can damage the system.
Maintaining the System C-5