Hardware Reference
In-Depth Information
the switch. This usually does not require complete disassembly of the keyboard. Periodic vacuuming
or compressed gas cleaning prevents more serious problems with sticking keys and keyswitches.
Most ball-type mice are easy to clean. In most cases, a twist-off locking retainer keeps the mouse ball
retained in the body of the mouse. By removing the retainer, you cause the ball to drop out. After
removing the ball, you should clean it with one of the electronic cleaners. I recommend a pure cleaner
instead of a contact cleaner with lubricant because you do not want any lubricant on the mouse ball.
Then, wipe off the rollers in the body of the mouse with the cleaner and some swabs.
To keep optical or laser mice clean, just check the bottom of the mouse for any dust or debris that
might block the light or detector. Use compressed air to remove dust or other extraneous material.
Passive Preventive Maintenance Procedures
Passive preventive maintenance involves taking care of the system by providing the best possible
environment—both physical and electrical—for the system. Physical concerns are conditions such as
ambient temperature, thermal stress from power cycling, dust and smoke contamination, and
disturbances such as shock and vibration. Electrical concerns are items such as ESD, power-line
noise, and radio-frequency interference. Each of these environmental concerns is discussed in the
following sections.
Examining the Operating Environment
Before you set up a new PC, prepare a proper location for it that is free of airborne contaminants such
as smoke or other pollution. Do not place your system in front of a window; the computer should not
be exposed to direct sunlight or temperature variations. The environmental temperature should be as
constant as possible. Power should be provided through properly grounded outlets and should be
stable and free from electrical noise and interference. Keep your system away from radio transmitters
or other sources of radio frequency energy.
Note
I also don't recommend using computer desks that place the system unit in a sealed cabinet; this
is a good way to promote overheating.
Heating and Cooling
Thermal expansion and contraction from ambient temperature changes place stress on a computer
system. Therefore, keeping the temperature in your office or room relatively constant is important to
the successful operation of your computer system.
Temperature variations can lead to serious problems. If extreme variations occur over a short period,
signal traces on circuit boards can crack and separate, solder joints can break, and contacts in the
system can undergo accelerated corrosion. Solid-state components such as chips can be damaged
also, and a host of other problems can develop.
To ensure that your system operates in the correct ambient temperature, you must first determine your
system's specified functional range. Most manufacturers provide data about the correct operating
temperature range for their systems. Two temperature specifications might be available, one
indicating allowable temperatures during operation and another indicating allowable temperatures
under nonoperating conditions. Many manufacturers list the following temperature ranges as
acceptable for most systems.
