Back Up Next

Chapter 3 *

Safety and Preventive Maintenance *

Certification Objectives *

Preventive Maintenance Products and Procedures *

Manufacturer Suggested Guidelines *

Liquid Cleaning Compounds *

Cleaning Contacts and Connectors *

Cleaning Tools *

Floppy Drive and Tape Head Cleaning *

Hard Drive Maintenance *

Determining Wear and Tear *

Vacuuming *

Environmental Hazard Protection *

Power Issues *

UPS (Uninterruptible Power Supply) *

Suppressors *

Noise Filters *

Storage of Components *

Lasers and High-Voltage Equipment *

From the Field *

Common Sense May Not Be So Common *

Lasers *

High-Voltage Equipment *

Power Supply *

CRT *

Disposal Procedures *

Batteries *

Toner Kits/Cartridges *

Computers *

Chemical Solvents *

CRTs *

MSDS (Material Safety Data Sheet) *

ESD (Electrostatic Discharge) *

ESD – What It Can Do *

Hidden ESD *

Common ESD Protection Devices and Procedures *

Hazardous Situations *

Certification Summary *

Two-Minute Drill *

 

Chapter 3

Safety and Preventive Maintenance

Certification Objectives

Preventive Maintenance Products and Procedures
Environmental Hazard Protection
Lasers and High-Voltage Equipment
Disposal Procedures
ESD (Electrostatic Discharge)

In the previous chapter, we discussed troubleshooting and repair procedures. In this chapter, we discuss the products and procedures used for preventive maintenance of computer systems and associated peripherals. Following this, we discuss safety issues that you should become familiar with to ensure that you do not injure or kill yourself during the repair or upgrade process.

Preventive Maintenance Products and Procedures

Preventive maintenance is something that customers often forget or do not believe is necessary. However, nothing could be further from the truth. For example, suppose you have a customer who frequently reschedules their preventive maintenance time. Because you are unable to perform the maintenance, neither of you would be aware that the fan in the power supply had stopped working. As a result, instead of just having to replace the power supply, the processor and some of the memory failed due to the excessive heat. In addition, the unscheduled downtime resulted in a loss of productivity and a larger bill from you.

As you can see from the preceding example, by performing regular maintenance on computer equipment, you can extend the life of the components themselves as well as locating potential problems. In the long run, this will save the customer time and money. In the next subsections, we discuss the various products available on the market along with the proper procedures for using them.

Manufacturer Suggested Guidelines

Before beginning any preventative maintenance procedures, it is critical that you consult the manufacturer’s documentation. Vendors include the information on the proper cleaning materials to use when cleaning or maintaining their components. Failure to follow these guidelines could result in either component degradation, complete failure, or a voided warranty. Never assume that you already know what you can use with what device; instead, take the time to review the documentation. Remember that customer service is not only solving a problem, but also ensuring that you do not generate them.

Liquid Cleaning Compounds

There are several liquid cleaning compounds that are used when you perform preventive maintenance. However, it is important to keep in mind that you should always refer to the manufacturer’s documentation prior to using any cleaning compound on a component. This is because every vendor may use different materials in the component itself. In addition, some vendors require specialized cleaning compounds that can be purchased from them.

Various forms of alcohol are frequently used in cleaning computer components, such as isopropyl alcohol and denatured alcohol. These items are generally used to clean contacts and are applied to special disks used for cleaning floppy drive read/write heads. Mild detergent can be used on the outside of the monitor, the computer case, and on keyboards.

Cleaning Contacts and Connectors

Few people realize, or remember, that contacts and connectors require cleaning. The reason people forget is because connectors are seldom removed from their respective sockets. Nevertheless, these items do get dirty over time and do require cleaning. Most components can be cleaned with a cotton swab that has been coated with isopropyl alcohol. However, many manufacturers recommend that you use a pencil eraser to clean the contacts on expansion cards. As with most computer components, it is important that you consult the vendor’s documentation to ensure that their product will not have an adverse effect from the materials that you use.

Cleaning Tools

There are several cleaning tools that you should keep in your maintenance kit. One nice item to have is a rubber knife. When you are called upon to remove hardened residue from metal components, you can use a rubber knife to dislodge particles that the vacuum or dust-free cloth could not remove. Never use a metal knife or other metallic object when cleaning the computer or its components, as you can either damage them or cause injury to yourself through electrostatic discharge (ESD). ESD occurs when two charged objects come into contact with each other, such as your hand against a door knob. The charge is transferred between the two objects until both objects have an equal charge.

Compressed air comes in handy when you are cleaning components, such as a keyboard, or areas that a vacuum can not get to (or shouldn’t get to!). Compressed air is distributed in an aerosol-type can and is available at any computer or electronics store. The air is compressed in the can, hence its name, by extreme pressure and dispelled through a nozzle that is similar to the old aerosol cans. You would use compressed air when you need to blow dust, dirt, or other unwanted debris out and away from a component.

Dust-free, lint-free disposable cloths or wipes are also cheaply available and should be used whenever you need to wipe the surface of a component. Normal cloths naturally attract lint and dust, while dust-free or lint-free cloths do not. This helps to ensure that you are not contributing harmful materials to sensitive components.

Floppy Drive and Tape Head Cleaning

When you’ve determined that the read/write heads on a floppy drive need cleaning, you need to obtain a floppy drive cleaning kit. The kits contain a special cleaning disk that looks like a normal floppy and a small bottle of isopropyl alcohol. The disk has an access hole, similar to a regular disk, on which you place a few drops of the isopropyl alcohol. Then you insert the disk into the drive and the drive will spin up. When the read/write heads attempt to read it, the disk will spin over the heads and clean them. These kits are relatively inexpensive and can be found at most computer and electronics stores.

When you clean a tape drive, you are performing the same function as with a floppy drive. The only difference is that you would use a special tape-cleaning cartridge instead of a cleaning disk with isopropyl alcohol. The cleaning cartridge looks exactly like a normal tape cartridge, although some manufacturers use a different color (usually white or beige) casing around a cleaning cartridge to help differentiate it from a normal cartridge.

Hard Drive Maintenance

Because hard drives are sealed units that can only be opened in a "clean room," there is nothing you can do to clean the read/write heads. However, hard drives have a tendency to become fragmented over a period of time or with excessive use and should be defragmented as a part of normal preventative maintenance. To perform a defragmentation, you can use a special software program that was designed specifically for this purpose, such as Norton Utilities or Microsoft Disk Defragmenter.

Another problem with hard drives is that the disk surface can become corrupted over time. If the drive attempts to read or write to these corrupted sections, the computer could crash or exhibit strange symptoms that are difficult to pin down. Some software utilities, such as the Microsoft Scandisk utility, are designed to locate and mark corrupted sections on the disk. The mark tells the hard drive to ignore this section of the hard drive. This process should be performed on a regular basis in conjunction with a disk defragmentation.

Determining Wear and Tear

Computer peripherals are not only electrical components, they are also mechanical components. These components wear out over time and eventually fail. As a service technician, you should inspect peripherals for signs of deterioration and replace any components that are about to expire. By doing so, you will save the customer time and money from untimely downtime when the component finally fails. Signs of wear can include thin spots on belts, bends or tear in cables, and moving parts that are only sporadically functioning.

Vacuuming

Most people do not realize it, but it is important to vacuum the inside of a computer case whenever you open it. Dust and dirt particles get sucked into the case through the air ducts and deposit themselves anywhere they can. These particles can conduct an electrical charge, resulting in possible damage to the delicate electronic components inside. Most offices do not have a vacuum that you will be able to use, as there are usually cleaning crews that carry their own equipment with them. However, small, portable vacuums are available for as little as $20 and are well worth the investment.

Whenever you have to open a printer for repair, it is important that you vacuum out the interior. Bits of paper and dust have a tendency to accumulate on the inside of a printer at a rate that exceeds the interior of a computer. The reason that this happens is due to the nature of the printer; that is, producing output on paper medium. Small bits of paper can tear off and become lodged inside the printer from clearing a paper jam. The dust produced during the printing process itself also contributes to the mess. As stated earlier, dirt and dust can carry an electrical charge. This small charge can be enough to damage the electrical components inside of a computer, as well as causing excess wear and tear on mechanical components that will have to work a bit harder against the dirt.

Environmental Hazard Protection

Computers must have a reliable source of power in order to function. However, there are many problems with our power supply that have the potential to damage computer systems and their individual components. The uninterruptible power supply (UPS) is a device that was designed to protect your computer and its components from possible injury from the problems that are inherent with today’s existing power supply structure.

Power Issues

With society’s increasing demand for power comes a price. The power utility companies have been hard-pressed to keep up with the present demand, leading to problems in dealing with future increases. As a result, brownouts, which are the momentary lapses in power supply, have become more common than they used to. Brownouts can cause problems with computer components that are not designed to withstand these events. Blackouts are similar to brownouts, as they are also lapses in power, but they are long-term power outages.

When there is a power spike, there is a sudden, huge increase in power that lasts for a split second. Power spikes can literally fry computer components. A power surge is similar to a spike, except that a power surge may not have the intensity that a spike can have.

As stated previously, noise creeps into a power line and is transmitted to the computer. This noise is almost impossible to keep out of the power line due to the vast distances involved and the technology used to transmit power. Noise is a one of the most prevalent problems with the power supply today.

UPS (Uninterruptible Power Supply)

Today’s UPS units are populating homes and businesses at an increasing rate as the cost has decreased substantially from the early days of computer history. The UPS is designed to protect your computer from sudden lapses in power, power spikes or surges, and "dirty" current. This is accomplished by several components in the UPS, such as suppressors, noise filters, and surge protectors. Each of these items are discussed in the following paragraphs.

Suppressors

At times, your power outlet will experience momentary surges of current, called spikes. Spikes can harm computers and their components much in the same way as ESD damage. However, the damage that results is usually on a much greater level, with catastrophic damage becoming more frequent. A suppressor is designed to either absorb or block the excess power and thus save computer components from injury.

Noise Filters

When someone refers to "dirty current," they are talking about the noise present on the power line itself. This noise is caused by electro-magnetic interferance (EMI) and can stray, or leak, from the current into nearby components. When EMI leaks from power current, it is called a magnetic field and can easily damage computer components. UPS’s contain a special filter, called a noise filter, that reduces the amount of noise present in electrical current and eliminates magnetic fields caused by noise, thus providing some protection to the components that utilize the current or are nearby.

Storage of Components

A UPS is essentially a battery that is designed to take over when there is a power loss, in addition to ensuring that only the proper type and form of current is passed on to the computer. When you need to store a UPS, you must ensure that is has not been discharged. A discharged UPS that is stored for a long period of time may lose some of its capacity to store power or may become unable to accept a charge at all. To ensure that your UPS is stored in the proper manner, review the manufacturer’s documentation for any other recommended procedures.

With other computer components, you need to protect them from damage resulting from electrostatic discharge (ESD). ESD occurs when two charged objects come into contact with each other and energy is transferred between them. This transference of energy happens to equalize the charge between these two objects. A good example of ESD is when you grab a door knob, or other metal object, and get shocked. Computer components are very sensitive to ESD and can even be rendered useless. Whenever you store computer components, you must place them in an anti-static bag to ensure their safety from ESD. Anti-static bags are designed so that static build-up is contained on the outside of the bag rather than on the inside, thus protecting the delicate components.

Lasers and High-Voltage Equipment

Whenever you work around lasers or high-voltage equipment, you must be extremely careful not to injure yourself. These forms of equipment can cause damage in the form of burns, eye-related problems including blindness, or even death. There are procedures that should be followed whenever working with either high-voltage equipment or lasers. These procedures are discussed in the following subsections.

From the Field

Common Sense May Not Be So Common

In the years that I have been doing PC repairs, I think I’ve seen it all. Many techs (who of course are not A+ certified) make big mistakes that can ruin hardware and jeopardize data. One would think that a tech would not plug a monitor in after carrying it in a downpour of rain. The result: lots of smoke, and an expensive monitor that needs to be replaced.

Or how about the tech who tries to "hot dock" hardware accessories on a system that does not support this method. (Hot docking is the ability of a system to accept new accessories while it is plugged in.) I’ll tell you from first-hand experience that a hard drive will not be able to be plugged into the system while the power is on. If you try it, the result is a hard drive that is completely erased.

Never force anything. This is how RAM sockets get broken, causing replacement of the motherboard. If the processor does not fit right, do not try to force it in. The result will be spending the next hour with needle-nosed pliers trying to get all the pins straight again, or worse—a broken pin and a fun time explaining to your supervisor what happened.

If you drop a screw in the machine, never just leave it there. It could end up against two contact points and really mess things up. Take the time to find and remove the screw. Plug a power cord in backwards and you will see smoke. Turn the power switch on the back of the machine from 120volt to 240volt and you might as well grab some marshmallows. Start trying to repair the monitor when you don’t fully understand the voltage involved, and I’ll say a prayer for you.

Be careful in what you do. Fires, lost data, personal injury, and damaged hardware are very real events. Your best protection is to know exactly what you are doing at all times and to be careful. If you are in doubt about anything that you are doing, do not be afraid to ask some who knows. No one is supposed to be able to fix everything. If you are in over your head, do not proceed.

By Ted Hamilton, MCP, A+ Certified

Lasers

Lasers employ a high-intensity light beam that can cause severe damage to your eyes, including blindness. Never look directly into a laser beam. Some lasers can cause severe burns when they come into contact with skin, or even death depending on the intensity of the beam and the location on you. However, the lasers employed in CD-ROM drives are Level 3 laser beams and are of a significantly lower intensity than those employed in construction or scientific applications. As a result, you will not get a severe burn from them but should nevertheless be cautious when working with them.

The laser that is employed in laser printers is also a Level 3 type of beam. However, laser printers do generate an excessive amount of heat, and components that reside inside these printers can cause severe burns. It is for this reason that you should be extremely cautious when working inside a laser printer.

High-Voltage Equipment

You should exercise extreme caution when working around any high-voltage equipment, including any equipment near the computer itself. You can spot these items from one of two types of labels on the equipment itself. The first type of label is a Warning label that usually informs you of the potential of equipment damage as well as personal injury. The second type of label is a Caution that tells you of possible personal injuries that can occur. Most labels refer to a procedure or set of guidelines to be performed whenever you work on the equipment, although some refer you the equipment’s documentation for more information. It is always important to follow the manufacturer’s guidelines whenever working on or around high-voltage equipment. Failure to follow these instructions to the letter can result in severe burns or electrocution.

There are a few considerations that you should keep in mind whenever you are working on or around high-voltage equipment. First, never wear an ESD strap around this form of equipment, as the electrical charge could kill you. Second, be especially aware of the electrical pathways on your person. This means that you should never use both hands on the equipment itself. If you do, you are forming a "live" circuit between you and the equipment, resulting in an electrical pathway that leads from one hand and passes through your body to the other hand. The first sensation is one of extreme pain as your skin is cooked where you have come into contact with it. The second is the acrid odor of burning flesh. When electric current passes through your heart, the end result is death as your heart cooks and your blood boils from being heated by the electricity. If the current reaches your head, your brain will become well-done and your eyes could burst out of their sockets. If this is an intensive, sickening graphical description of what can happen when you are not careful, good! It cannot be stressed enough how important it is for you to be extremely cautious around any high-voltage equipment and to be aware of the environment around you.

Power Supply

A power supply is the perfect example of high-voltage equipment. As discussed in Chapter 1, these devices convert the alternating current (AC) that comes from your regular power outlet into the direct current (DC) that your computer uses. Therefore, you want to ensure that the computer is turned off and that the power cord has been disconnected from the power supply.

When the power supply performs the power conversion process, some of that energy is lost and converted into another form of energy: heat. The heat generated by a power supply can cause severe burns. Therefore, it is important for you to ensure that the power supply has had sufficient time to cool down before coming into contact with it.

If you ever open a power supply, you risk severe shock or even electrocution from the electrical charge stored in the capacitors located within the power supply itself. This is true even if the power supply has been off for a long time, as the static electricity that builds-up over time can get into deadly ranges. As a result, never remove the case from a power supply. Remember, while a power supply is a replaceable component, you aren’t.

CRT

Monitors are high-voltage components that should only be repaired by experienced personnel. When working on monitors, it is important to remember that extreme caution should be taken at all times, as any built-up charge can be lethal. However, the first thing to remember is never wear an ESD wrist strap when handling monitors. After you have removed your wrist strap, ensure that the monitor is powered off and disconnected from the power outlet. This is an important step because you have to discharge the monitor.

To discharge a monitor, you need to have a jumper wire and a screwdriver with a non-conductive handle. First, connect one end of the jumper wire to a ground such as the screw on an electrical outlet. Next, wrap the free end of the wire around the metal shaft of the screwdriver. When you do this, make sure that the wire is as far away from the shaft of the screwdriver as possible. This helps to prevent any accidental contact between you and the wire.

Assuming that you have already removed the casing from the monitor, locate the anode lead that is attached to the glass inside the monitor. An anode lead looks like a small suction cup with a wire connected to it. Do not touch the anode lead or the wire! Using the tip of the screwdriver against the underside of the anode lead, gently pry the lead away from the monitor until you hear a small "pop" or the lead is free of the glass. The small "pop" sound is any built-up charge that has accumulated on the glass. This charge will pass into the screwdriver and follow the jumper wire into the ground. If you should come into contact with either the shaft of the screwdriver or the jumper wire while the monitor is being discharged, part of that charge will enter your body and can cause severe injury. However, at this point, the monitor has been safely discharged.

EXAM WATCH: Know the procedure for properly discharging the monitor. Not only for your own safety, but because most people who take the exam get two or three questions on this procedure

Disposal Procedures

Once you have replaced a component, the next question is what to do with it. Landfills used to be the answer, but these areas have proven to be only a short-term solution. Environmental concerns have also become an issue as harmful chemicals have a tendency to leak into the water table and contaminate our drinking water supply. As a result, most states have enacted stringent rules and regulations regarding the disposal of any item deemed harmful to the environment. Recycling of these hazardous substances has become a more viable, long-term solution. As a service technician, you need dispose of the various computer components and chemicals that you use in an environment-friendly manner.

For more information regarding hazardous waste and proper disposal procedures not discussed in the following subsections, you can visit the EPA’s Hazardous Waste Resource Conservation and Recovery Act page at http://www.epa.gov/epaoswer/osw/hazwaste.htm

Batteries

Batteries contain environmentally harmful substances and should not be disposed of through a convenient trash can. The Battery Act passed by Congress on May 13th, 1996 was designed to phase out the use of mercury in batteries and to provide for the recycling or proper disposal of nickel-cadmium batteries. However, each state has different rules and regulations regarding the proper reclamation and disposal of batteries. To ensure that you follow the appropriate procedures for your location, check with your state’s environmental regulatory office before disposing of used batteries.

For more information on The Battery Act, obtain the document from the United States Environmental Protection Agency Web site at http://www.epa.gov/epaoswer/hazwaste/state/policy/pl104.txt

EXAM WATCH: Every A+ Certification Exam will have at least one question on battery disposal.

Toner Kits/Cartridges

Toner cartridges are recyclable items. Normally, the vendor will take your old toner cartridges when you order new ones, and will even give you a small credit for doing so (who says recycling doesn’t pay?) However, if you are unable to exchange the cartridge, ask the vendor if they have any information or suggestions on the proper disposal method. If, for some reason, they cannot assist you, contact your state’s environmental regulatory office for the appropriate disposal measures.

Computers

Old computers need not be thrown away if they are still usable. There are many churches and public schools in dire need of computers, and will accept them as a donation. By doing so, you receive a write-off on your taxes for a charitable contribution. However, if the computer is so antiquated as to be useless or the computer is beyond repair, there are many companies that will buy them for spare parts or as scrap metal.

Chemical Solvents

Chemical solvents are materials that are considered hazardous waste. The reason for this is the liquid gets absorbed in the ground and eventually makes its way into the water table. Never dispose of these items by emptying them into a sink or toilet. Proper disposal of chemical solvents is regulated by the Environmental Protection Agency and your local state government. As each state’s rules and regulations are different concerning the disposal of these materials, you need to check with your state’s environmental regulatory office for the proper procedure.

CRTs

If a monitor still functions, it is a good idea to keep at least one around for testing purpose. However, if you have enough monitors on hand, you can donate them to any church or public school for a tax break. If the monitor is useless, check to see if the manufacturer included disposal instructions with the monitor or contact the manufacturer directly. Some manufacturers will accept the monitor and give you a small credit when you purchase a new one. However, if neither of these options are available, you need to check with your state’s environmental regulatory agency for proper disposal procedures, as monitors are no longer acceptable to landfills.

MSDS (Material Safety Data Sheet)

Material Safety Data Sheets (MSDS) are white pages that contain information on any substance that is deemed hazardous, most notably cleaning solvents. MSDS is required by the United States Department of Occupational Safety and Health Administration, and must be posted in obvious locations. The purpose of MSDS is to inform employees about the dangers inherent in hazardous materials and the proper use of these items to prevent potential injuries from occurring. For more information on MSDS, please consult their Internet site at http://www.osha.com.

ESD (Electrostatic Discharge)

A computer is not just a valuable resource, it is a costly one. As we become more dependent on them in our everyday lives, the most expensive feature is the time wasted by a malfunctioning computer, called downtime. As an example, suppose you have over 600 people on a network server that goes down for over four days. While they wait on the server to be repaired, they are not only unable to perform any work, but you still must pay them. Once the server is operational again, it could take an entire week’s worth of overtime for them to catch up with the workload, costing you even more money and many missed deadlines. It is because of these types of expenses that you must ensure that the computer is repaired as soon as possible.

One of the things that can cause downtime is damage to delicate computer components through a common phenomenon called electrostatic discharge (ESD). Everyone has been shocked at least a dozen times when grabbing a doorknob or other metal object, and you probably even see a spark when it happens. When an object can conduct electricity, such as a computer component or the human body, it has a tendency to retain some of that energy. That energy, known as static electricity because it doesn’t move, builds up in an object over time, and is said to be charged. When two objects come into contact with each other, electrons are transferred between them until they both have an equal charge. This electron transfer is an electrostatic discharge.

ESD – What It Can Do

While ESD may not hurt you, it can still harm a computer component. Most devices operate between the three- to five-volt range, and can be damaged by ESD charges as low as 30 volts. When you actually feel the shock caused by ESD, that energy transfer is over 3,000 volts. Even worse, if you can see a spark when ESD occurs, that discharge is in the vicinity of 20,000 volts. Unless precautions are taken, you can actually destroy a device without even realizing it. This type of damage is called catastrophic damage because the device is rendered inoperable.

One other type of ESD damage can be caused: degradation. A component that suffers from degradation may continue to operate for days, or even months, before failing entirely and could damage other components while it is functioning. Depending on the severity of the damage, a device may even pass a diagnostic test. However, the components can cause intermittent problems in the computer that are extremely difficult to pinpoint, causing frustration to both the client and the technician and extending the downtime required to repair the computer.

Hidden ESD

The term "hidden" ESD refers to a couple of things. A static discharge that you do not feel can be considered hidden ESD because you will not even realize that it has occurred. Remember that when you feel ESD, you are receiving a charge around 30,000 volts. Charges that are below 30,000 volts can still damage electronic components.

Another form of hidden ESD is in the form of dust and dirt. As discussed in an earlier section, dust and dirt particles are capable of carrying an electrical charge. This charge is capable of destroying computer components over time, as the particles can pick up a charge and transfer it to a component several times. Unless you can keep your computer in a "clean room," which is a special sealed room that contains almost no dust or dirt, you will have to schedule regular cleanings for computer system to cut down on the chances of catastrophic damage to computer components.

One last item to consider is the humidity level in the room. A humidity level below 50 percent tends to lead to static electricity. You will notice this especially in the winter months, when humidity levels are low naturally. Ensure that you check any air-handling equipment in the room for a properly set humidity level. However, ensure that the humidity is not set too high, as high levels condense the water particles in the air and these particles stick to computer components. Remember, water is a natural conductor of electricity as well!

Common ESD Protection Devices and Procedures

There are several forms of ESD protection devices, such as mats, wrist straps, and bags. These items should be used whenever you are working with computer components to prevent ESD damage.

ESD mats are made of an insulate material that is designed to slowly bleed away any excess charge from whatever comes into contact with it. There are two wires with alligator clips, one clip connected on the end of each wire, that are attached to the mat. When you use an ESD mat, you should first lay out the mat on a flat surface, such as a desk or a workbench, that is near an electrical ground. Next, you attach the first wire to an electrical ground, such as the screw on an electrical outlet, using the alligator clip. Never attach the clip to the electrical socket itself as you can electrocute yourself in this manner! Place the computer, or component, on the mat and connect the second wire to the computer. This safely transfers any static electricity that has stored up in the computer or the device and directs the charge into the ground. However, if you are working on a monitor, do not connect the second wire as you need to discharge the monitor according to the procedures discussed earlier in the chapter.

ESD wrist straps are also made of an insulate material and are worn on your wrist to safely bleed off any excessive charge stored in your body. The strap commonly has a Velcro fastener on it and a metal button that has a wire attached to it. To properly use an ESD wrist strap, you need to put it on and connect the wire to an electrical ground. The wire connects to the ground using an alligator clip that is attached to the end of the wire. Make sure that the ground is close to the work area and that you are aware of where the wire is at all times. Some ESD straps have a long wire that can be tripped over as you move around the work area.

ESD bags are the anti-static bags in which computer components are shipped. These bags are designed to collect stray electrical charges on the outside of the bag as opposed to the inside. Thus, the component stored inside the bag is kept safe from ESD damage. Always store computer components in ESD bags to ensure that they are kept as free as possible from dust and dirt as well as from ESD damage. As these bags are handy items to keep around, ensure that you have a good supply of them for storing old, but still functional, computer components. You can do this by keeping the bags that new components have shipped in rather than throwing them away. This saves you money, as you need not purchase them at an electronics store, and it helps protect the environment by keeping them out of landfills.

You can also purchase anti-static sprays to use on carpets and fabrics to reduce the build-up of static electricity. It is a good idea to spray these surfaces that are anywhere near your work area. In addition, ensure that you are wearing shoes that contain a rubber sole so that you do not build up any static electricity between yourself and the carpet as you walk around.

Hazardous Situations

Because there are many hands that touch the electronic components, from the people who manufactured the equipment to the packaging plant, ESD is not something that you can entirely eliminate. However, there are things that you can do to control the potential for harm to electronic devices and injury to yourself. The first thing is to ensure that you are not wearing any jewelry while working on a computer system. Watches, rings, necklaces, bracelets, and earrings all contain metal parts that conduct electricity. In addition, these items themselves can cause damage to components, as well as you, if the jewelry gets caught on anything inside the chassis. If you still don’t believe it, imagine an earring getting caught on a cable as you lift your head out of the chassis!

Another thing that you can do to minimize the possibility of injury to yourself and computer components is by always following the ESD procedures discussed earlier in this section. Always place components on an ESD mat and, unless you are working on a monitor or a high-voltage device, always wear your ESD wrist strap. It cannot be emphasized enough that you must remember to take off the wrist strap when working around monitors or high-voltage devices. The charge that builds up in monitors, even after they have been powered off for a long period of time, can prove lethal. And never pack computer components in anything other than ESD bags. You can place the bags in boxes or packing peanuts, but only after the bag has been properly sealed with the component inside.

While the newer computer operating systems, especially network servers, enable you to repair them while the computer is still running, it is extremely important that you follow the manufacturer’s guidelines to the letter. When live current is running through a computer, you are faced with the possibility of severe burns or even death. All it takes is a moment’s contact with the wrong component and you could become history. Always take the extra time to review the vendor’s guidelines before performing the repair.

Certification Summary

Preventative maintenance is one of the most important aspects in ensuring a healthy computer system. The tools and materials that are used during this process are equally important, as using improper equipment or cleaning products can result in harm to the delicate components. In addition, it is important to remember that the computer can become dangerous if you are not careful when working on it. Hazards can include anything from high-voltage equipment to electrostatic discharge, and preventative measures must be taken to ensure that you and the computer are not damaged. This chapter has discussed all of this in detail in order to arm you with the knowledge to prevent severe injury, or even death, to you.

Two-Minute Drill

A discharged UPS that is stored for a long period of time may lose some of its capacity to store power or may become unable to accept a charge at all.
As a service technician, you should inspect all computer peripherals for signs of deterioration and replace any components that are about to expire.
The lasers employed in CD-ROM drives are Level 3 laser beams and are of a significantly lower intensity than those employed in construction or scientific applications.
Batteries contain environmentally harmful substances and should not be disposed of through a convenient trash can.
ESD occurs when two charged objects come into contact with each other, such as your hand against a door knob. The charge is transferred between the two objects until both objects have an equal charge.
It cannot be emphasized enough that you must remember to take off the wrist strap when working around monitors or high-voltage devices.
A component that suffers from degradation may continue to operate for days, or even months, before failing entirely and could damage other components while it is functioning.
It is important to keep in mind that you should always refer to the manufacturer’s documentation prior to using any cleaning compound on a component.
Never use a metal knife or other metallic object when cleaning the computer or its components, as you can either damage them or cause injury to yourself through electrostatic discharge (ESD).
ESD mats are made of an insulate material that is designed to slowly bleed away any excess charge from whatever comes into contact with it.
Always take the extra time to review the vendor’s guidelines before performing any repair.
Noise is a one of the most prevalent problems with the power supply today.
One of the things that can cause downtime is damage to delicate computer components through a common phenomenon called electrostatic discharge (ESD).
Power spikes can literally fry computer components.
When you are called upon to remove hardened residue from metal components, you can use a rubber knife to dislodge particles that the vacuum or dust-free cloth could not remove.
Signs of wear on peripherals can include thin spots on belts, bends or tear in cables, and moving parts that are only sporadically functioning.
The laser that is employed in laser printers is also a Level 3 type of beam.
Never remove the case from a power supply, else you risk severe shock or even electrocution from the electrical charge stored in the capacitors located within the power supply itself.
To discharge a monitor, you need to have a jumper wire and a screwdriver with a non-conductive handle.
Various forms of alcohol are frequently used in cleaning computer components, such as isopropyl alcohol and denatured alcohol.
When a power supply performs the power conversion process, some of the energy is lost and converted into another form of energy: heat.