Taking care of your computer; when was the last time you cleaned your computer? Ernest E. Mau.
Taking Care Of Your Computer
When was the last time you cleaned your computer? I don't mean a fast wipe with a cloth or a quick pass with a vacuum cleaner, but a complete job on inlets, fan filters, card connectors, and under the keytops. Be honest. If it has been more than a month, you have committed a cardinal sin of computer usage.
Many recreational and professional computer users overlook or ignore conditions that contribute to unnecessary failures and malfunctions. You can minimize these conditions to extend the operating life, improve overall performance, and reduce repair costs. Specifically, the areas of concern are dirt and contamination, excess heat, stray magnetic fields, electrostatic charges, power disturbances, and mechanical wear.
Dirt and Contamination
Anything existing outside a sealed environment gets dirty, if only from airborne dust and contaminants. This includes computer systems; dirt is the mortal enemy of any system.
A few years ago, most computers were housed in special rooms where temperature and humidity were regulated, air was filtered, and activities such as smoking, drinking and eating were prohibited. In large corporations using mainframes, you still find glass rooms, walled off from the rest of the world.
With the advent of the personal computer, however, machines have been moved into open, uncontrolled environments. The new breed for homes, professional offices, stores, and similar installations had to be accessible to people, with a corresponding increase in problems resulting from dirt and contamination.
Modern microcomputers are exposed to dust, smoke, soot, chemical pollutants, fine particulates known as "aerosols,' and corrosive gases, with little or no thought about the effects. There are no totally clean offices or homes. The average office is full of cigarette smoke, urban pollution, and dust. The average home has airborne cooking grease, pet hairs, and carpet fibers, among other unsavory things in the air.
Add particles of human hair, dandruff, upholstery fibers, and bits of food, and you begin to understand what the computer must endure. More problems are particles of printer paper, oxide from tapes or disks, and fibers broken loose from printer ribbons.
Computer equipment cannot be airtight. Components generate heat and require a continuous flow of cooling air provided by either natural convection or fans. Because more air flows through fan-cooled machines, they collect more internal dirt than convection-cooled ones and generally require more cleaning and care.
Dirt can cause anything from a gradual decline in performance to outright failure, and problems often build slowly until a malfunction occurs.
Dirt on outer surfaces usually isn't serious. Dirty screens are hard to read. Dirty keys feel strange; dirty covers are unsightly. External surfaces are cleaned easily, however, and cause few operational difficulties.
Dirt inside the system is a serious problem. Though contaminated drives and disks aren't readily spotted, they show up as data misreads (I/O errors), head "crashes,' damaged disk surfaces, or random intermittent errors.
Dirt blocking the cooling air allows heat to build up, leading to damaged components and costly repairs. Contaminated connectors (cable and circuit board) and switches can fail to make good contact or can make and break contact intermittently. Even the telephone plugs of modems and other communications devices can be contaminated, leading to data transmission errors and the loss of expensive network time.
Furthermore, some contaminants are conductors, creating unwanted electrical paths and short circuits. Graphite particles from pencils, soot, metallic chips, and magnetic oxides are particular problems.
Preventive and Remedial Steps
The best cure for dirt-related problems is prevention, primarily through regular inspections and cleaning.
On the installation level, replace filters on forced-air heating and cooling systems every two or three weeks. In dry climates, install a room or furnace humidifier to reduce both airborne contaminants and static-electricity problems. Portable room-air filtration devices also help, but the filters must be changed frequently. Furthermore, such units must be kept several feet from the computer and magnetic media to avoid potential problems from electromagnetic fields.
Beware of auxiliary heating devices, especially kerosene heaters and wood stoves. Even the most efficient kerosene heaters emit a kerosene mist. When the mist condenses on surfaces, circuit boards, chips, disks, tapes, and screens, it leaves a greasy, conductive film that can do immeasurable damage. As a rule, if you own a computer, don't use a kerosene heater anywhere in the same building. Similarly, wood stoves are "dirty' devices that lead to the unavoidable spread of ash, smoke, and dust. Though not as damaging as a kerosene film, these contaminants must be removed from both the outside and inside of the computer, perhaps as often as three or four times a week.
Clean your installation, system components, and surrounding area every week. Vacuum the floors, baseboards, window sills, and furniture. Wipe down desk or table tops, component casings, and other exposed surfaces with a soft, damp cloth or a commercial cleaning product intended for computer use. Be certain the cleaning cloth is damp, not wet. Avoid detergents--they leave residues that later cause more contamination. Avoid chemical solvents, particularly degreasing chemicals--they can damage components.
Make use of the many cleaning products available for computer and electronic equipment. Screen-cleaning solutions, pressurized clean-air canisters, and lint-free cloths are essential for proper care of your equipment. Make a special point of obtaining and using a disk-drive cleaning kit, preferably one that contains a special disk and solutions so that drive heads can be cleaned simply by inserting the disk and activating a drive for 30 seconds or so. It voids your warranty or service contract to open drives and clean them with swabs.
Inspect all air vents and intakes, giving special attention to filters and fan housings where screens or filters may block the air flow. Replace or clean filters and screens in accordance with the manufacturer's recommendations.
Check the cables to printers, terminals, disk drives, and modems. A common cause of systems failures and communication problems is a loose connector, and many connectors work loose simply from the normal operating vibration of fans, disk drives, and printers.
At least once a month, inspect the inside of your equipment chassis, assuming of course you can open it without endangering a warranty or service contract. Be sure power is off and the power cord disconnected before opening anything, then remove the covers and look for accumulations of dirt and dust. Remove any such accumulations, especially around boards and connectors. Tweezers and a canister of pressurized clean air are useful tools for removing dirt. Do not reverse the hose of a vacuum cleaner and use it to blow into a device--if you have tried reversing a hose, you probably have seen puffs of dirt and dust emitted, and the last thing you want is to introduce that dust into your equipment.
Check mechanical components for evidence of wear. Look for worn spots on moving surfaces inside printers, especially on the rails and bearing surfaces of the printhead and print hammer. Be sure to clean paper chips and accumulated paper fibers from inside the printer. If the disk drives can be opened, check the rails on which the heads ride, and look for "burn marks' and abrasions on the magnetic heads. Also look for excessive deposits of oxide worn from disks, indicating a possible problem with either the heads or the disks themselves. Check all guide rails in printers and disk drives for dust and dirt that may interfere with smooth tracking. Follow the instructions in your manuals concerning lubrication of mechanical parts. If your manuals don't cover care and maintenance, contact the manufacturer and request or purchase a service manual.
Once or twice a year, be prepared to strip, clean, and reassemble your equipment--or pay a technician to do it for you. Remove circuit boards and clean the edge connectors and sockets. Check the seating of all integrated circuits. Check the seating of all cable connectors. Remove the keytops from the keyboard and clean out accumulated dirt. Basically, perform a minor overhaul.
Heat buildup is a sneaky hazard that catches unwary users by surprise. All equipment has manufacturer-specified operating and nonoperating temperature ranges that must be observed. In general, personal and small-business computers and peripherals can operate successfully under ambient temperatures from 50~F to 80~F (10~C to 26.6~). That range covers the limits of normal operator comfort, typically 65~F to 78~F (18~C to 25.5~C). It is important to maintain the operating environment within the specified range. If the temperature is too low, mechanical actions such as disk accesses and printing may become sluggish. If too warm, overheating may cause improper operating and anything from a total shutdown to intermittent errors.
Remember that electronic and mechanical devices generate heat, which, if not vented or cooled, can cause internal temperatures to exceed the ambient temperature. It is the internal temperature that causes difficulties, and it must be controlled so that the equipment can function normally. Often it is necessary to install special cooling devices on the equipment. Slotted covers and auxiliary fans may be necessary to maintain satisfactory operating temperatures.
Particular heat problems occur when plug-ins are added to computers, with each unit adding its own heat to the total and possibly exceeding the cooling level for which the unit was designed. With smaller machines, the situation is compounded by vertical component stacking, where disk drives are placed on top of the computer and a monitor is on top of the drives. That creates a vertical heat column, in which upper units block the cooling of lower ones, while lower units add to the heat built up in higher ones.
The usual cause of excess heat is blockage of air intakes. Such blockages result from installing a unit having left insufficient air space around it, placing something over the vents, or allowing dirt deposits to collect on filters or screens. Internal dirt also blocks the flow of air around critical components.
Never install computer equipment above or near heat sources. Stay at least three feet from heating vents or radiators. Keep at least six feet from auxiliary space heaters, including electrically powered radiant heat panels and stoves. Because of the double threat from heat and contamination, don't put the computer in the same room with a kerosene heater or wood stove--preferably not in the same building.
Less obvious is the danger from direct sunlight. Sunlight striking the machine generates heat beyond the levels with which the cooling air flow can cope. Heat radiated by window glass, drapes, carpets, and furniture exposed to sunlight adds more problems. Furthermore, sunlight can warp disks and magnetic tapes, leading to loss of valuable data.
Often, the first sign of a heat problem is erratic operation, including numerous errors during data processing. Extended exposure to excess heat shortens the life of circuit chips and other components, eventually leading to more failures under various operating conditions. The cumulative effects can be devastating and expensive.
According to one report, "Studies have shown that the life of electronics equipment is cut in half for every 10~C rise in temperature. So if you keep your . . . computer 10 degrees cooler, you double its life and also increase its reliability during normal operation.'1
1 "Frequently Asked Questions about VENTOP,' unpublished report (1982), Tovatech, 1903 Fordham Way, Mountain View, CA 94040.
Preventive and Remedial Steps
No system should ever be damaged by heat since heat problems can be prevented. By keeping the equipment away from sources of direct heat and out of direct sunlight, you have most of the problem licked. If you like to look out the window while you work, consider putting a commercial reflective window film on the glass in the computer area. Bronze- or silver-tone reflective film is inexpensive compared to computer failures; it's easily installed, and it substantially reduces the heat generated by direct sunlight. However, don't rely totally on reflective films--some heat gets through; so draw the drapes as often as you can.
Keep the equipment clean, both inside and outside. Take care not to obstruct air intakes, vents, fan inlets, and other openings, either by placing something in the way or allowing dirt and dust to accumulate.
Third, allow sufficient space for free air flow. Never jam a unit up against a wall or set it on a soft surface like carpeting. Even foam vibration pads are dangerous to components having air intakes on the bottom (the "feet' sink in and the clearance to the bottom is reduced).
Don't stack components vertically; instead spread them out horizontally. That avoids concentrating the rising heat and creating an additive thermal column that easily overheats the uppermost units. I don't care for most commercial workstations used to house systems in a minimum area, because many of them concentrate the heat sources while they block the free flow of cooling air.
Install additional cooling whenever possible. Be especially alert to auxiliary fans marketed for units normally cooled by convention. Often potential heat problems aren't evident until the system has been on the market a while and manufacturers begin providing plug-ins. Then someone sees a heat-related failure and realizes that convection cooling isn't adequate for a fully-equipped unit or that the cooling fans have been undersized. The appearance of auxiliary fans on the market for a specific brand of equipment indicates that extra cooling is required.
Magnetic or electromagnetic fields are hazardous because they can disrupt computer operations, alter data being processed, and erase magnetic storage media.
Every electrical current and, thus, every electrical or electronic device generates an electromagnetic field--some weak, others strong. Motors, bells, buzzers, and transformers contain electromagnets, and some also have permanent magnets. All have electromagnetic fields. Even computer components generate fields, including ribbon-lifters of printers, disk drive motors, and fransformers in monitors and terminals. Furthermore, loose ferrous (iron-based) metal objects may be magnetized, including screwdrivers, pliers, wrenches, tweezers, scissors, paper clips and staples.
Like other hazards, the effects of stray magnetic fields are unpredictable, showing up as drive failures, memory losses or alterations, garbled data, garbaged printouts, pulsating displays, unexpected breaks or transmission errors in network communications. The most damaging is erasure of magnetically stored data. Interference with electronic operation is transient and generally causes little or no permanent damage to hardware, but lost data can be expensive.
Preventive and Remedial Steps
Most problems with electromagnetic fields are avoidable. Remove the source of the field and the problem is gone. It is difficult to know which item causes the problem, and people tend to overlook the obvious.
One offender is the phone. Because its bell operates with a powerful electromagnet, putting the phone next to a box of disks could damage the contents of the box when the phone rings. Similarly, placing the phone near disk drives or memory circuits may interfere with storage and processing operations.
Audio speakers are a source of trouble for people who like music while they work. Speakers have powerful magnets to move the cones. In turn, the magnetic fields damage disks, tapes, memory contents, and read/write operations if not located a sufficient distance away.
Just moving offending devices three to six feet from the computer is usually sufficient. But be careful not to put them where you could walk through a field with a disk or tape in your hands. In general, keep anything not required for computer operation away from the machinery, including tools, flashlights, intercoms, and any other device of metallic nature or which operates from an electrical outlet.
Be careful of video terminals and monitors, reserve power supplies, and similar devices. They often contain powerful transformers with fields that can devastate memory storage and mass media quickly. Some tape and disk devices are particularly sensitive and cannot be run within two or three feet of a CRT or monitor. That's another reason for not stacking a monitor on top of disk drives--the transformer can prevent proper read/write operation and can even erase disks while they spin in the drives.
If a divce cannot be relocated, try shielding it from the other components with a thin sheet of soft iron or carbon steel. Often such an insert is sufficient to block the magnetic field and protect the sensitive components. Protect your magnetic media at all costs. Store tapes and disks in dust-protective jackets and boxes at least three to four feet from any electrical or electronic device. Never leave magnetic media on top or beside the computer, drives, monitor or CRT, or printer. Never allow them near the telephone, speakers, calculators, or similar gadgets.
Static electricity, a constant problem around computers, is always a potential source of malfunction. A good description of the phenomenon is provided by The State Control Systems division of the 3M Company:
"In scientific terms, it is an imbalance of electrons on the surface of a material. Whenever two materials that are in contact are separated, an imbalance of electrons occurs each surface, resulting in a positive charge (deficiency of electrons) on one surface and a negative charge (over-abundance of electrons) on the other surface. Because this charged state is "unnatural,' each surface makes an effort to discharge, or return to its neutral state. A typical example . . . is a person walking across a floor (generating a static charge) and then getting a shock (discharging) as a door knob is touched. Quantitatively, when a person feels this shock, a charge of at least 2500 volts is involved, a charge level high enough to cause malfunctions of electronic equipment . . . charges well below 2500 volts can cause equipment malfunctions, so static protection may be needed even though "shocking' is not present.'2
2 Robert J. Kunz, "The Solution to Static Caused Problems with Commercial Electronic Equipment: 3M Static Control Floor Mats,' Report JSFMP(501)R1, Static Control Systems/3M.
All floor surfaces are potential problems--carpeting, vinyl tile, wood, and concrete. Furthermore, moving objects such as the flywheels and diskettes in continuously spinning disk drives are internal sources. Even paper moving through a printer can build and carry a charge.
Eliminating carpeting doesn't cure the problem. The 3M Company report cites experimental work done at Western Electric Co., determining that the most common buildup for a person walking across a carpet was 12,000 volts; walking across a vinyl tile floor under the same environmental conditions accumulated 4000 volts. The highest readings reported were 39,000 volts for carpeting and 13,000 volts for vinyl tile. Carpeting generates higher voltages, but solid floors still generate enough to be dangerous to delicate equipment.
Contrary to popular belief, high humidity does not eliminate static. Although high humidity reduces charges and danger, it does not get rid of static.
The most obvious static effect is a spark from one object to another. But even when arcing isn't evident, static can damage the inside of electronic devices or data stored on magnetic media.
Static can alter or wipe out the contents of memory, generate faulty data, blank a video display, cause unwanted printer carriage returns, and create a host of similar problems. Worse, static discharges can burn out circuit chips or entire circuit boards. A discharge to magnetic media can permanently destroy data or even damage the magnetic surface.
Interface cables are particularly vulnerable. Sometimes cables have to be routed where it is possible to step on them. Simply walking across the floor can discharge static into the cables, thereby "clobbering' the devices at either end. This can lead to lost data, blown circuit chips on interface boards, fuse failures and system shutdowns, or damaged circuit boards. In network communications, the cords that connect the computer and the modem are entry points for static that disrupts the communications, garbles the transmissions, and generally incurs increased time and charges for the network use. At worst, static penetrating a telephone cord could damage the modem itself or the computer to which it is connected.
Expect static to cause erratic computer behavior at all levels from disk operations through network communications. Be alert to the possibility even if you don't see any sparking; if you get a spark when touching the equipment, you have a problem that has to be eliminated.
The best cure for static is prevention. Ensuring that every component is grounded serves as a good first step, but it isn't foolproof. Be certain the third prong (the round one) of every line plug is properly grounded. Do('t attempt to defeat the grounding by cutting or bending the prong and don't attempt to use two-prong adapters without connecting their pigtail wires. If you have any doubts about the electrical grounds in your building, it pays to have an electrician check or install them before you hook up your computer system.
Other steps that reduce but don't entirely eliminate static problems are removing carpets and rugs from the working area, installing a humidifier, avoiding crepe or rubber soled shoes, and avoiding excessive movement such as shuffling your feet while working.
Connecting cables should be routed so that they can't be stepped on or touched. Putting them under a carpet may help avoid tripping, but static discharges can penetrate the carpet to reach the cable and connected electronics.
Sometimes commercial anti-static sprays are helpful in cutting down short-term problems, but they must not be sprayed directly onto the keyboard, screen, or magnetic media. The residue left behind could cause problems later. Some sprays irritate the eyes, so be careful where and how you use them. Remember, you will have to repeat the treatment periodically: vacuuming the carpet or wiping the desk surface removes or degrades the antistatic protection.
You can achieve effective, long-term solutions to static problems with antistatic floor mats placed under chairs, behind counters, and in other locations where people walk and come in contact with delicate electronic devices. They are also useful on top of connecting cables (between devices and to communications modems) as a means of preventing discharges into the cables. Conductive anti-static mats must be connected to a good ground to be effective, usually to the center screw of a grounded wall receptacle. Sitting or standing on such a mat then grounds static built up while you walk to the installation and prevents buildups while you move around at the equipment.
Power disturbances are the biggest pain of all, both to stand-alone computer operations and network communications. If the lights don't go off completely, low voltages (brownouts), surges, spikes, line noise, and other problems wreak havoc with computer operations and data transmissions. Basically, there are three major types of disturbances: power outages, voltage fluctuations and line noise. All are disruptive and all can be destructive.
Did you know that you are the one responsible for providing appropriate power and installing protective devices? Did you know that failure to condition your power lines can be considered negligence and cause for voiding warranties or canceling service contracts? Did you know that neither the manufacturer nor the retailer is responsible for problems resulting from your failure to meet power specifications?
It is common to receive line power above or below the maximums and minimums specified for a piece of equipment. If the specification calls for 115 VAC nominal with a maximum of 130 VAC, utility lines carrying 131 VAC are "out of spec,' and it is your responsibility to detect the condition and do something about it.
Most power disturbances originate on the utility lines, resulting from causes as diverse as power switching, damage to underground cables, lightning strikes on lines and transformers, and auto accidents knocking out distribution boxes. Of course, you can overload a circuit and blow a breaker or fuse, create interference or noise with appliances, or generate other problems of your own, but the most serious and the most difficult to control begin outside your installation.
One effect of a power outage or blackout is a sudden shutdown of the computer system, losing programs and data in memory and whatever results have been computed to that point. That is typical of interruptions lasting more than a few power cycles. Shorter interruptions cause glitches which in turn cause erroneous results or data transmissions, alter programs, trash displays or printouts, disconnect network links, and so on.
Those are just operating errors; much worse can happen. A high-voltage surge can figuratively "fry' equipment, burning out circuits or entire boards. Internal power supplies can burn out. Mechanical parts can jam, with the possibility of severe damage. Disks can crash, possibly damaging heads or magnetic media. If the magnetic medium isn't physically damaged, stored data may be erased or altered. Files may be irretrievable.
Not only are power disturbances damaging to the system, you can't predict, prevent, or control them. You can, however, spend the time and money to protect the most vital components and operations against them.
You are the only one who can determine how much protection you can afford, how much your applications justify, and which of several alternatives is suitable. For instance, recreational users might be able to afford and to justify protection only against voltage spikes, which is relatively cheap with "surge protectors' costing upward of $25. Other users may want to guard against both surges and electrical noise, usually requiring a combination of surge protection and line "isolation' in devices costing from $60 to $200.
On the other hand, protecting against short-duration power interruptions and brownouts using standby power supplies can cost from $250 to $1200 for small personal computers and many thousands for large-scale professional systems. Business users with critical applications may have to spend considerable sums to achieve multi-purpose protection against numerous disturbances. Yet, those expenditures may be justified by eliminating equipment damage and losses of vital data.
The number of available power-conditioning devices is staggering. At the low end of the price scale are inexpensive in-line surge suppressors and noise filters that guard against sudden increases in line voltage and against electrical noise that might be imposed on lines by appliance motors and other devices. Effective for mild disturbances on residential and commercial power lines, they do not safeguard equipment or data from outages, and most give limited protection against severe surges or the extreme noise typical of industrial facilities.
Heavy duty devices are available at added cost, providing improved protection against severe spikes and surges while eliminating potential electrical interactions between devices plugged into the individual sockets. Actually, if you can afford one, such heavy duty suppressors and isolators are preferable to the inexpensive home units. If you use your computer strictly for entertainment, an "industrial strength' isolator and suppressor will give you a definite edge.
For those with the money to spend, standby power supplies and uninterruptible power supplies are by far the best. Standby supplies are available in sizes from about 200 watts to megawatts and at prices from about $3000 to many thousands of dollars. However, the average home or small-business user probably can get by with a 200-watt unit for a personal computer or something between 500 and 1250 watts fo a professional or business system. The advantage to these power supplies is that they provide automatic switch-over to temporary battery backup power during an outage or severe low-voltage condition. Furthermore, they typically include surge suppression and noise filtration with the standby power.
True uninterruptible power supplies, known as UPS units, differ in that they power the computer equipment continuously from batteries and charge the batteries while the incoming line is active. When line power is interrupted, batteries continue to output without any switchover. Like the standby units, these are available at many prices and in many sizes. However, a UPS unit of a given power rating typically costs more than a switching reserve supply of the same rating.
Wear and Tear
Physical were affects the moving parts in printers, disk drives, tape transports, keyboards, and switches. Since the component used most often wears the fastest, input-oriented systems probably will have more wear on the keyboards while output-oriented systems will have more wear on the printer.
The effects are twofold, leading to gradual decline in performance or an abrupt failure. In the first, the system starts showing a few minor problems, but they quickly multiply. One key might not register every time, then another and another. Disk I/O errors you saw once a month become weekly, then daily, then hourly. Printouts get fuzzy and indistinct, especially when compared to ones done months earlier.
Or there can be a sudden failure without warning. A printer abruptly stops feeding ribbon or paper; a disk drive spins the disk but can't seem to access any data; a power switch may not work to turn the equipment on or off.
The best protection, in fact, the only protection against wear is keeping the equipment clean, properly lubricated and operating at design temperatures. There is no way to eliminate wear and stress on moving components, but you can minimize their effects.
Suitable lubrication is particularly important and must be provided in strict accordance with any schedules or procedures in equipment manuals. Failure to lubricate moving parts quickly runs up high repair bills; mechanical parts are much more expensive to fix than electronic ones. Excess lubrication isn't acceptable either, because it leaves residues that attact dirt, increase friction, and cause more wear. Watch out for parts that should not be lubricated, with special attention to the rails and components of the disk drives. Most maintenance manuals warn against lubricating the rails that support the read/write heads.
Be sure to use only those lubricants approved for the units or parts. There is no such thing as a universal oil, and one component like a letter-quality printer may need a dozen or more different lubricants. Of course, many high-grade lubricants are expensive, and stocking multiple types gets costly. Even service shops and technicians usually don't stock them all--a reason they don't volunteer often to clean and lubricate a machine.
If there is a wear- or stress-related failure, there is little to do except to replace the part or parts or to pay to have them replaced. However, you should be aware that it is hard to find a good source of repairs for mechanical components. Almost any hack can fix computer electronics by hit or miss replacements until the problem goes away. But mechanical units like letter-quality printers take some training and skill to repair, often requiring total machine realignment and adjustment for replacing a single small part. If fact, it is often necessary to send something like a printer back to the factory or to a regional service depot to get the job done right.
In this article, I have tried to give you some insight into what is really involved in caring for a small computer. Regrettably, a magazine article doesn't afford space to cover a subject like this in the detail it deserves. Whole books can be written just on cleaning procedures, and those are just one aspect of the total picture.
It is important to look for the obvious. Take care of dirt, excess heat, magnetic fields, static charges, power disturbances, and lubrication, and you have solved most of the problems. By doing some routine tasks, you improve the odds in favor of a long, happy relationship with your computer system.