Introduction

You should now be familiar with proper installation and configuration procedures for many computer devices. You should also be familiar with determining when components need to replaced or reconfigured. In this chapter, you will learn about procedures you can perform to prevent problems from occurring in the first place. You will also learn about procedures you should follow so that you do not cause damage to computer components or cause harm to yourself or the environment.

4.1 Preventive Maintenance Products and Procedures

Regular cleaning of computer components can extend a computer’s life. For example, by regularly cleaning the power supply fan, you can ensure that it is able to properly cool the computer’s internal components. Regular cleaning can also help stop problems before they start, as in dust build-up inside a mouse. Giving a computer a regular cleaning also gives you a good opportunity to inspect the computer’s components and determine if the potential for a problem exists.

For example, while cleaning the system, take note of loose components or connections and tighten them up. You should also look for frayed or cracked cables and replace them, even if they have not yet caused a problem.

Liquid Cleaning Compounds

Before using a liquid cleaner on any device, make sure that the computer is off and that the component is completely dry before you turn the computer on again. In addition, note that you should stick to the procedures discussed within this section. That is, do not use a type of liquid cleaner on a device other than the ones discussed here. For example, if you were to use water rather than alcohol on the floppy drive, you might cause permanent damage to it. Some of the cleaning components are shown in Fig 4-1.

Fig 4-1 Cleaning Components.

Some computer components, such as a mouse ball, the mouse casing, and the case on the monitor and computer itself, can be cleaned using mild, soapy water or a damp (not wet) cloth as shown in Fig 4-2. In short, most plastic external coverings in the computer system can be cleaned this way. Make sure that no liquid drips on the components.

Fig 4-2 (a)

Fig 4-2 Cleaning a Mouse.

If the keyboard is sticky, you can clean it with plain, distilled water. Make sure that you unplug the keyboard from the computer, and make sure that the water contains no impurities such as soap or iron. Ensure that the keyboard is entirely dry before reattaching it to the computer. Keyboard can also be cleaned with a Vacuum cleaner or a brush as shown in Fig 4-3.

Fig 4-3 (a) Cleaning a Keyboard using handheld vacuum.

Fig 4-3 (b) Using Brush.

Some devices are harmed by water and/or soap and should be cleaned with denatured (isopropyl) alcohol. For example, the cleaning liquid that comes in most floppy drive cleaning kits is alcohol. You can also use alcohol to clean any residue on a mouse roller that you can’t remove with your fingers.

Cleaning a CRT

The preventive maintenance associated with monitors consists of periodic cleaning, dusting, and good, commonsense practices around the monitor. Aerosol sprays, solvents, and commercial cleaners should be avoided because they can damage the screen and cabinet. You can use a regular glass cleaner to clean the screen on a CRT monitor. Follow the steps in Exercise 4-1 to properly clean a monitor.

Cleaning an LCD monitor

The life and usefulness of the portable’s LCD panel can be extended through proper care and handling. Cleaning an LCD monitor is different from a glass monitor. You can usually clean an LCD monitor with non-abrasive glasses cleaners, such as those from Lens crafters, or by using a water mist and an eyeglass cloth to dry the monitor. Spray the cleaner on the cloth and then wipe the screen. Never spray the cleaner directly on the screen. Avoid glass cleaner, alcohol, or other solvent-based cleaners. Follow the manufacturer’s cleaning instructions to avoid scratching or damaging the plastic cover of the monitor. Cleaning a monitor is shown in Fig 4-4.

Exercise 4-1Cleaning a CRT Monitor

1. Shut down the computer.2. Turn the monitor off and unplug it from the electrical outlet.3. Spray a small amount of glass cleaner on a clean cloth or paper towel.4. Use the cloth to rub fingerprints or other smudges off the monitor screen. Be careful not to let

any cleaner drip.5. Allow the glass cleaner to completely evaporate (about a minute).6. Plug the monitor back in and turn it on.

Fig 4-4 (a) A Glass Cleaner

Fig 4-4 (b) Cleaning a Monitor.

Cleaning Contacts and Connectors

It’s a good idea to check your system’s contacts to make sure that they are establishing a good connection. Bad connections cause malfunctions. You can clean connectors using contact cleaner. Remember to make sure that your computer is unplugged and turned off before doing any preventative maintenance.

Removing Dust and Debris from the System

One of the most common reasons to clean a computer is to remove dust buildup. Recall that the power supply’s fan draws air into the computer and distributes it over the internal components. It can do the same thing with dust. Because dust can cause ESD (electrostatic discharge) and lead to overheated components, it’s important to clean the inside of the computer regularly. Pay particular attention to the system board, the bottom of the computer chassis, and all fan inlets and outlets. Make sure you power down the computer before you start cleaning it.

Smoke is a more dangerous cousin of dust. Like dust particles, smoke collects on all exposed surfaces. The residue of smoke particles is sticky and clings to the surfaces. In addition to contributing to the heat-buildup problem, smoke residue is particularly destructive to moving parts such as floppy disks, fan motors, and so forth.

Note: Be aware of the effect that missing expansion-slot covers have on the operation of the system unit.

Fig 4-5 (a) Compressed Air

Fig 4-5 Removing dust using Compressed Air.

Dust buildup inside system components can be taken care of with a soft brush. One of the easiest ways to remove dust from the system is to use compressed air to blow the dust out. Compressed air comes in cans that are roughly the size of spray-paint cans. Using a compressed air is shown in Fig 4-5. Typically, a liquid at the bottom of the can compresses the air and forces it out when you depress the can’s nozzle. If you turn the can upside-down, you can cause the liquid to be released. Avoid doing so; the liquid can cause freeze burns on your skin and damage the computer’s components. You should also be aware of where the dust is being blown. That is, make sure that the dust is not being blown from one component only to settle on another. You can also use compressed air to blow dust out of the keyboard, expansion slots, and ports.

Another common method for removing dust is to vacuum it out. This has the advantage of removing dust without allowing the dust to settle elsewhere. It is best to use a special hand-held vacuum that allows you to get into smaller places and clean the computer without accidentally hitting and damaging other internal components. Remove the nozzle from inside, and move the vacuum cleaner away from the computer before turning it off.

Finally, you can use a lint-free cloth to wipe off dusty surfaces. Avoid using the newer dust cloths that work by “statically attracting” dust. Remember, static is harmful to the computer.

Note: Compressed air is more effective in cleaning places that are hard to get at, but vacuums cause less mess.

Keyboards have become extremely inexpensive. They tend to range in price from less than $10 to $80. In many cases, it is not worth the time to do much repair work or anything more than a superficial cleaning. If the keyboard is misbehaving, replace it.

Another good way to clean the keyboard is to simply turn it upside-down and shake it. You’ll probably be surprised at the amount of stuff that falls out. If this doesn’t do the trick, use a can of compressed air to blow debris out of the keyboard, or use a small hand-held vacuum. Some types of crud can be stubborn, and you could end up having to remove each keycap to properly clean the keyboard. Use a flathead screwdriver to pry the keycap(s) off. (Make sure that the computer is off before you do so.) To replace a keycap, simply orient it the right way and snap it into place. Be careful of the Spacebar; it sometimes contains springs that can fly out and disappear. Taking the keyboard apart like this can be very time-consuming, so it should really be a last resort.