preventive maintenance 3

8/6/2019 Preventive Maintenance 3

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Domingo M. Caya Jr.


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There are many aspects to system care and

maintenancethat affectthe system as a

whole, or every component in the system, as

opposed to being specificto a particularcomponent. These factors are discussed in

this section.


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In the last few decades we all have become

much moretuned into our external

environment and how it affects us. Well, it

affects your PC as well. We're much moreimportantthan PCs of course, but as it

happens, many of thethings that make

humans sick or uncomfortable,have a similar

impact on computers. This section takes alook atthese issues.


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The general rule of thumb for room

temperature is that PCs likethe

temperatures that (average, normal :^) )

people like. Generally speaking, goodoperating temperature for a PC is about 60

to 75 degrees Fahrenheit (15 to 24 or so

Celsius). Cooler than this is of course, better

than warmer.


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Operating a PC in a hot room that is over 80

degrees Fahrenheitcan make itvery difficult

to cool. Remember that some businesses

havethermostats on a timer that will makeair conditioning shut off at night; in this

situation you might wantto make sure a PC

is not left running overnight, or that a

special computer room is designated withindependentcontrols.


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Most PC hardwarecan tolerate being at much

lower temperatures (or moderatelyhigher

temperatures) when they are not running. If

you aretransporting equipment or storing it,thetemperatureconcerns are much less than

if theequipment is actually in use. However,

if youhaveequipmentthathas been exposed

to very low temperatures and is thenimmediately turned on, you risk permanently

damaging theequipment.


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If youtake a PC that is at freezing

temperature and plug it in, it will warm up

veryquickly, much morequickly than it

would if you left it on a tableto warm up inits own time. In somecases, youcan raise

thetemperature of equipment from 0

degrees to 150 in only a matter of minutes.

Thermal stress is a leading cause ofpremature failure of electronics components.


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Even more dangerous than this is the

possibility of condensation


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It is quite possible for this to happen with

electronicequipment as well. This does not

cause any problem as long as you givethe

condensation enoughtimeto evaporate. Ifyour hard disk platters are "moist" when you

spin them up, you risk destroying the drive.


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Much as thecase is withtemperature,

computers prefer moderatehumidity as

opposed to either extreme. PCs are not as

sensitiveto humidity issues as they aretotemperature, butthey are still affected by

it.


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Obviously,computers and moisture don't mix

well; you need to keep your computer dry.

That means keeping it away from places or

things thatcan get it wet. This includes theobvious: don't put a PC in the bathroom or

kitchen, for example. It also includes


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Humidity leads to corrosion and possible

condensation risk, whichcan damage

equipment. It also makes cooling the PC

more difficult. Conversely, air that is too drycan cause problems in two different ways.


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First, it increases the amount of static

electricity that is in the room, increasing the

chances of a discharge. Second, itcan cause

faster wearout of somecomponents that dryout over time. This includes sometypes of

capacitors, as well as rubber rollers on laser

printers.


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Finally,humidity can exacerbate problems

related to dramaticclimatechanges. Going

from a cold environmentto a warm onecan

lead to condensation, which is why you mustwait for the PC to warm up beforeturning it

on. Obviously, if the warm environment is

also a humidone,thechances of

condensation are increased


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Computers operate best when they areused

in a clean environment, and when they are

cleaned regularly. Most offices and homes

areclean enoughthat a PC requires nospecial treatment other than regular cleaning

as part of routine preventive maintenance.

Industrial environments however can be

murder on PCs.


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PCs that are going to beused in dirty

circumstances should be protected or

cleaned more often. Oneeasy preventive

measure is to use an air cleaner in the roomwherethe PC is located. There are also

special cases and enclosures for PC hardware

designed for industrial environments to

safeguard against damage dueto dirt. Theaverage PC owner only has to remember to

clean their equipment occasionally and no

problems will generally result.


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Many problems,especially unreliable storage

devices, are related to cigarette smoke

accumulating on read/writeheads and

media.


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All electronic devices give off

electromagneticemissions. This is radiation

that is a byproduct of electrical or magnetic

activity. Unfortunately,theemissions fromone devicecan interfere with other devices,

causing potential problems.


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Interferencecan lead to data loss, picture

quality degradation on monitors, and other

problems with your PC, or problems withother devices such as television sets and

radios. These are generally categorized as

electromagnetic interference or EMI

problems.


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Two different issue

EMIemissions by the PC,

EMIemissions received by the PC.


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PCs generally do notcausevery much

interference with other devices;they are

required by the Federal Communications

Commission (FCC) to becertified as Class Bdevices.

This certification is used to show thatthe PC

conforms to standards that limitthe amount

of EMIthat a PC can produce.


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The only catchto this is that youhaveto

keep thecover on the PC. This is one reason

why thecover is always made from metal.

(Keeping thecover on is also an importantpart of ensuring proper ventilation).


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PCs can be affected by electromagnetic

interference from other devices, in two

major ways

directeffects through proximity with otherdevices

electrical interference over the power lines.


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EMI if youthink it is affecting your PCs:

Physical Isolation: Devices thatemit

electromagnetic radiation should be kept areasonable distance from your PC, peripherals

and media. This includes television sets, radios,

lights, kitchen appliances, and stereo speakers

(the ones designed for use with PCs are generally

shielded and are much less of an issue).


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Use Dedicated Circuits: Many office

buildings especially,have separate power

circuits that are intended for use by PCs.

Keeping your PC on a circuitthat is separatefrom thecircuit running your refrigerator

and air conditioning unit means thatthere

will be much less interference passing to the

computer from the other devices (and this

will also improvethequality of the power

being sentto your machine in general).


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Power Conditioning: Theuse of a line

conditioner or uninterruptible power supply

can filter out interferencecaused by otherdevices that share a line with your PC.


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keeping your system cool is very important. A

cool system runs more reliably and lasts

longer than onethat runs hot. Overheating of

the internal components can lead to dataloss or even damageto your equipment. In

recent years, as processors in particular have

gotten faster and hotter,the subject of

cooling has become more importantthan

ever.


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Internal Air Flow

The "first line of defense" in cooling the overall

system is the fan that is used to provide overall

air flow within the system case. This is normallythe fan located within the power supply atthe

back of thecase; some newer machines,

especially full-tower cases,employ morethan

one fan,to provide morecooling.


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It's importantto realizethatthe fan (or fans)

used in thecase and/or power supply work

by establishing a flow of air throughthe

case.


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There aretwo basic designs used.

In a standard baby AT stylecase,the power

supply fan blows outthe back of the power

supply, and in doing so it draws air throughtherest of thecase and thereby,cools the

components insidethecase.


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In the newer ATX style of case and power supply,

the power supply fan is on theinside of thecase

and blows inwards, pushing air throughoutthe

case and drawing it in throughthe back of the

power supply,exactly the opposite.


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In bothcases, for thecooling to work

properly,the flow of air must not be

interrupted. The better, and stronger,the

flow of air,the morecooling it willaccomplish. If the flow is notestablished

correctly, at best only some of the

components will becooled.


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General System Care

Factors


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preventive maintenance 3

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