Dell OptiPlex N, User Manual

Page: 22 / 38

2-4 Dell OptiPlex N and OptiPlex NX Systems User’s Guide
Magnetism
Because they store data magnetically, hard-disk drives
are extremely susceptible to the effects of magnetism.
Speakers
Audio speakers can be a source of magnetic energy if
they are not properly shielded. Speakers used in music
systems are typically enclosed in wooden cabinets, which
provide no magnetic shielding. Multimedia speakers for
computer systems are magnetically shielded inside a
metallic case and are thus the only type of speakers rec-
ommended for use with multimedia computer systems.
Shock and Vibration
Excessive shock can damage the function, external
appearance, and physical structure of a system. Excessive
vibration can cause the same problems as excessive
shock does and can cause components to become loose in
their sockets or connectors. Systems can be subjected 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 a left side (for vertical orientation using the
optional stand) and bottom half-sine pulse with a change
in velocity of 50.8 centimeters per second (cm/sec)
(20 inches/sec). In storage, the system can withstand a
26,478-cm/sec
2
(27-gravities) faired square wave with a
velocity change of 508 cm/sec (200 inches/sec).
Power Source Interruptions
Computer systems are sensitive to variations in voltage
supplied by the AC power source. Overvoltage, under-
voltage, and transients (or spikes) can erase data from
memory or even cause components to fail. To protect
against such problems, power cables should always be
properly grounded, you should use a power protection
device, and you should place the system on a circuit that
does not contain any heavy electrical equipment.
Your network administrator should verify your power
source and network cables; however, you should ensure
that your system is connected to a dedicated power cir-
cuit and that it is not sharing a circuit with any of the
following:
•
Kitchen appliances
•
Copier machines
•
Air conditioners
•
Vacuum cleaners
•
Space heaters
•
Power tools
•
Teletype machines
•
Adding machines
•
Any other motorized equipment
Another threat to a system’s supply of power is surges or
blackouts caused by electrical 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

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 voltage spikes that could damage the
system.
P
ower Protection Devices
Various levels of power protection are available for your
system.
Surge Protectors
Surge protectors prevent voltage spikes, such as those
caused during electrical storms, from entering a system
through the AC power source. These devices are avail-
able in a variety of types and usually provide a level of
protection commensurate with the cost of the device.