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 Safety |
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Caution:
Before working on PC
Maintaining a well-functioning PC requires that you do a lot more
than running an occasional ScanDisk or deleting temporary Internet
files. You need to follow some fairly extensive physical maintenance
routines, such as cleaning, bathing, shampooing…err….
you get the idea. This chapter goes through the important routines. Preventative Maintenance Procedures To prolong the life of your PC, you simply must inspect and clean it regularly. Cleaning your PC on a regular basis can prevent overheating and ESD. During the inspection process, look for damaged or cracked components improperly seated components, frayed cables, and loose connections. Liquid Cleaning Compounds Before using any liquid cleaning compound, make sure that your computer is turned off. If the PC has power when you use liquid cleaners, you run the risk of frying or shorting out your components, which is an expensive risk to take. Also make sure that the component you have cleaned with a liquid cleaner is thoroughly dry before turning your computer back on! Clean or Soapy Water and a Damp Cloth In
some cases, you need only a bit of water and a damp cloth for cleaning
chores, such as when cleaning the mouse ball, the outside of the mouse,
or the exterior of the monitor or computer case. If water alone cannot
do the job thoroughly, you can use mild soapy water on your damp cloth.
Make sure that the cloth is damp and not wet and that you do not splash
or drip water into your components.
The
best thing to use for cleaning floppy drive heads is denatured alcohol.
But how do you get in there? You can’t just pour it in! You
need to use a lint free swab dipped in the alcohol to clean the floppy
drive heads, or you can purchase a floppy drive cleaning kit, which
almost always comes complete with denatured alcohol. Don’t clean
the mechanical mechanism with alcohol because the parts are lubricated
and the alcohol will dissolve the lubricant. Glass Cleaner You need to turn your monitor off before cleaning to avoid damage to the screen. Many technicians clean the monitor screen with regular cleaner. Under most circumstances, however, water and a damp cloth will do the job just fine. Water is the safest cleaning liquid you can use on a monitor. When cleaning the LCD display screen of a laptop, do not use glass cleaner at all. You will melt the screen! Fabric Softener Some technicians like to use a mixture of 1 part fabric softener to 10 parts water to clean the plastic casing of their computer components. As a cleaning solution it’s not as good as mild soap and water, but as an anti-static solution it’s excellent! Use it after the cleaning process to help protect your computer from the harmful effects of static electricity. Cleaning Contacts and Connectors To protect your contacts and connectors from becoming dirty, avoid touching them with your hands. Your skin contains natural oils that can leave a residue on contacts and connectors, and that residue needs to be cleaned off. Leaving the contacts untouched will reduce the amount of residue and make them easier for you to clean. Erasers Some technicians use an eraser to rub residue off contacts, but this leaves a residue of its own and may actually rub the contacts right off. If you absolutely must use erasers, make sure you use the white ones, and immediately clean any rubber residue off the contacts. Never, ever use pink erasers to clean contacts as these contain acids that have the potential to destroy your contacts. Non-Static Vacuums Common household dust kills PCs. Throw in some dog and cat hair and you might as well call a priest right now. A dust buildup can cause dreaded static and can cause your components to overheat and become useless. When removing dust buildup from your keyboard, inside your computer’s case, and from your components, use a non-static vacuum (shown in Figure 2-1). Many hand-held vacuums are designed specifically for use on PCs. Note that you should definitely not use a common household vacuum cleaner. These create static electricity and can toast your PC! Compressed Air Compressed
air works well for getting the dust out of power supply fans, expansion
slots, and keyboards, but you need to exercise care in using it for
blowing the dust off components and the inside of the case. It is
not uncommon to blow the dust off one component right onto another
component. Lint-Free Cloths Lint-free cloths are excellent for removing dust from your computer. The cloths used for cleaning eyeglasses work the best, because they will not scratch surfaces or leave lint behind.
You need to protect your computing environment from any kind of power surges or power sags, as either of these events can cause severe damage to your system. Many things outside the control of normal folks cause sags and surges, such as electrical brownouts and blackouts, spikes on the electrical grid, lightning, and electromagnetic interference. Brownouts Power sags are usually caused by brownouts, where your lights may flicker or grow dimmer. In other words, power sag occurs when the supply of electricity drops dramatically but does not go out completely. When the power or electricity returns to its original level, your computer cannot handle the quick and drastic change and damage may occur.
Power surges are caused when the power or electricity goes out completely and comes back on suddenly. In the event of a power surge, any files that you have not saved will most likely become corrupted or lost forever. Power Spikes A power spike is a lot more powerful than a power surge and will almost definitely result in the damage of computer components. The damage caused by a power spike can irreparably affect one or several components. Lightning Storms Any time you use your computer, or even leave it plugged in, during a lightning storm you are asking for damage to occur. No commonly available PC accessory can protect your PC from the damage caused by electrical storms. You need to unplug your PC and peripherals with power cords until the storm ceases. Leave no stones unturned: make sure you unplug even your modem, because lightning can travel through the phone lines and cause damage to computers and their components through the modem. EMI EMI, or electromagnetic interference, is caused not by storms, but by noise created by high voltage between two cables or excessively long cables. When EMI occurs, your PC may experience sags and surges in the amount of electricity that is provided to it. The threat of EMI can be combated through the use of cables with a Mylar coating and through a noise filter, which will control the amount of electricity that reaches your PC and remove the EMI. Noise filters can be purchased as stand-alone products or can be incorporated into an uninterruptible power supply (more on those in the next section). Saving Your PC from Electrical Problems Any kind of power failure, sag, surge, or spike can cause irreversible damage to your PC and its components. So you simply must protect your PC from these events! Fortunately, many products on the market can help you prevent these events from damaging your PC. These products are called uninterruptible power supplies (UPS) and surge suppressors. Uninterruptible Power Supplies
A
UPS helps in blackout situations, during which the electricity cut
offs completely for a period of time, and brownouts, during which
the electrical supply sags well below the level needed to run your
PC. Every UPS has batteries that provide backup power, thus enabling
you to save your work and shut down your PC properly. A UPS is thus
sometimes called a battery backup. Note that a UPS does not provide
unlimited power so you can keep working while the city lights are
out. What it does provide you is a short window of a couple of minutes
to save and shut down. Standby Power Systems An SPS has a battery that begins generating power as soon as the unit detects a sag in the supply of electricity. It takes a split second for the SPS to come online, however, and therein lies the main disadvantage to using an SPS. The brief lapse of time could result in your files being damaged before the UPS has kicked in. Online UPSs An online UPS, in contrast to an SPS, provides electricity to the PC all the time, using the electricity from the AC outlet simply to recharge its batteries. If you have an electrical brownout or blackout, your PC does not even flinch, and you’ll have plenty of time to save and shut down properly. As an added bonus, most online UPS boxes act as power conditioners that help your PC run better. Electricity coming from the power company does not come in a single stream of electrons at constant pressure, but rather in gentle fluctuations. Because the online UPS runs the PC from its batteries, the UPS can provide a much smoother flow of electricity that the typical wall socket. An online UPS costs more than an SPS, but in the long run its benefits justify the expense. Surge Suppressors
Surge
suppressors help to absorb power surges so that your computer does
not feel their effects. They come as either separate modules or incorporated
with a UPS. The best suppressors to purchase are the ones with the
lifetime or 10-year guarantee. When purchasing stand-alone surge suppressor,
avoid the cheapest ones. They are usually little more than power strips
and provide minimal protection against power spikes. Storing Components for Future Use When
storing your computer components for future use, you still need to
prevent them from the hazards of ESD, corrosion, and other damage.
You should store your computer components in cool, dry places. Heat
or warmth can cause premature aging of your components in much the
same way that the sun can cause premature aging of your skin. Moreover,
heat can also destroy data that has been stored magnetically and dampness
can cause corrosion to your components. Potential Hazards and Proper Safety Procedures While power issues can cause damage to your PC, many hazards can injure the technician, such as high-voltage shocks or electrical fires. You need to make yourself aware of these hazards and of ways to prevent them from occurring. High Voltage Equipment The
capacitors in PC power supplies, monitors, and laser printers carry
very high voltages that can easily cause severe bodily injuries. Fortunately,
in most cases you will not have to worry about identifying high-voltage
equipment because it is usually marked by a bright yellow warning
sticker that will leave no question about the voltage levels of the
components. Power Supplies Whenever
you work on your computer, you need to make sure it is unplugged.
In the old days, you could leave the PC plugged in and thus ensure
excellent electrical grounding, but modern PC motherboards always
have a small voltage running when the PC is plugged in. Unplug the
PC or you’ll likely toast something. Monitors Never
open a monitor unless you know exactly what you are trying to accomplish.
The voltages inside can kill you. The capacitors in a typical PC monitor
also carry extremely high voltages even when unplugged. In addition
to the line voltage and capacitors, the flyback transformer is a dangerous
part of the monitor. Don’t know what that is? That’s a
good reason to keep out! Fires Most
of us will never experience a PC fire, but we may experience an electrical
fire in our homes. It is important that you realize that just as smoke
can harm you, it can also harm your PC and its components.
Many computer components, such as batteries, CRTs, chemical solvents, and toner kits (for printers), contain harmful ingredients. Don’t throw these items in the garbage! Many of these items can be recycled, and a hazardous waste program can remove most. Batteries Batteries for the computer often contain lithium, mercury, or nickel-cadmium, which means that if they were to be thrown in the garbage and carried off to a landfill site, they could contaminate the water and soil. You can take batteries to a recycling depot or, in some cases, send them back to the manufacturer. CRTs Many CRTs contain lead. If you dump them in the trash (and ultimately in a landfill), you may contaminate the soil and water in your area and poison people. Don’t do it! For this reason, CRTs must be recycled or turned over to a hazardous waste program. Toner Kits and Cartridges The
main concern about the disposal of toner kits and cartridges is that
there are so many of them. Most people go through several a years,
and if they were all thrown in the garbage, they would fill a landfill
site. There are many ways of dealing with toner kits and cartridges. Chemical Solvents and Cans Chemical solvents or cans for PC use (or for any other use, for that matter) contain many harmful chemicals that should not be placed in the ground. For this reason, you simply cannot throw these in the garbage or they may damage the soil and water supply. Instead, chemical solvents and cans must be picked up through a hazardous waste program. Material Safety Data Sheet Most compounds, chemicals, and components come with a Material Safety Data Sheet (MSDS) that contains information about the product as well as any warnings, safe disposal requirements, and safe methods of transportation. If an item comes without an MSDS, you can obtain one from the manufacturer or locate one on the Internet.
This chapter has mentioned numerous times about the danger of ESD, but now it’s time for some details. Dust and ESD are the two main enemies of your computer. To maintain your computer and to prolong the life of components, you need to learn about the effects of ESD and how to protect your computer from those effects. How ESD Is Apparent or Hidden A prime example of ESD, or electrostatic discharge, is the small shock you receive when you walk across a carpeted floor and then touch an object or a person. Zap! The electrical discharge doesn’t do you any lasting damage, but such a seemingly harmless shock will destroy computer components. In fact, even discharges well below the level that you can feel will still damage or destroy PC components-and you won’t even know! (Hey, that modem worked just fine a minute ago….What could have happened?”) Hidden ESD A real concern, and another good reason to clean your computer regularly, is that the dust buildup on PC components can cause an electrical charge that you probably will not be aware of at the time. In most cases, you will not even be aware that a problem exits until a component begins to behave erratically, and by that point it will be extremely difficult or impossible to pinpoint the original source of the problem. Catastrophic ESD Catastrophic ESD causes a computer component to fail immediately. When catastrophic ESD occurs, it will be obvious. You can remove the components and replace it with a new one, and it most likely will not affect any other components. Degradation Degradation occurs when the effects of ESD are not immediately apparent in their full force, and the effects gradually get worse and worse. Degradation will cause your components to work erratically and can make the original problem hard to recognize. This condition can affect your other system components and cause their failures also. Common ESD Protection Devices Many
devices are available that can help to protect your system from the
effects of ESD to ensure a longer life for your components. These
devices include anti-static wrist and ankle straps, anti-static mats,
anti-static floor mats, anti-static bags, and anti-static sprays. `Anti-Static Wrist and Ankle Straps Anti-static
wrist and ankle straps are composed of a wire with a 1 megaohm resistor.
They keep you at the same relative electrical ground levels as the
computer components on which you’re working, as long as you
set them up properly. Anti-Static Mats Anti-static mats are conductive mats that dissipate ESD. They look much like place mats or those baby-changing mats that come with diaper bags, except they have a small clip attached to them that you can attach to a wrist strap to provide a conductive surface for grounding out ESD. These mats make an excellent place to place your tools and your components when you work on a system. Anti-Static Floor Mats Anti-static floor mats look similar to anti-static mats, and they also have the clip that you can attach to a metal object for the purposes of grounding. The main difference is that you need to stand on the floor mats to ground yourself and protect against ESD. Anti-Static Bags Placing components in anti-static bags, as mentioned earlier in this chapter, will greatly help your efforts to prevent ESD. Anti-static bags have a special coating or contain small filaments that help dissipate any static charge present when you pick up a component wrapped in such a bag. Better bags resist moisture as well. Always put PC cards and components (drives, RAM, and so on) in anti-static bags. Note that regular plastic or paper bags will not protect your components. In fact, if you put a PC component in a plastic baggie, you will almost invariably damage that component. Don’t do it! Anti-Static Spray Anti-static spray is normally used to avoid static charges in your clothing. Although many people use these sprays to help protect their work areas from the effects of ESD, it is not recommended. If any of the spray touches your components, it could cause damage. Fabric Softener As mentioned earlier in this chapter, a mixture of 1 part fabric softener to 10 parts water is an excellent solution to use on a damp cloth to wipe down the plastic surfaces of your PC and monitor. This can protect them from the harmful effects of static. Potential Dangerous or Hazardous Situations Temperature
and the level of humidity outside can dramatically affect the risk
of ESD inside. If it’s cold and dry outside, like an Alaskan
winter, and the heater’s blowing inside, you are basically a
PC-smoking ZAP! Waiting to happen. You need to take precautions. |
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