Tải bản đầy đủ - 0 (trang)
Chapter 3.  System Maintenance and Assembly

Chapter 3.  System Maintenance and Assembly

Tải bản đầy đủ - 0trang

PreventiveMaintenance

Preventivemaintenanceisthekeytoobtainingyearsoftrouble-freeservicefrom

yourcomputer.Laptopsystemsareespeciallypronetoproblemsbecausetheyare

portableandthereforeexposedtopotentiallyharshenvironments,rougher

handling,andmoreproblemsthandesktopsystemsthatremaininasingle

location.Allittakesisanaccidentsuchasdroppingthelaptopontoahard

surfacetoturnthousandsofdollars'worthofcomputerintosomuchjunk.Alittle

carecombinedwithsomesimplepreventivemaintenanceprocedurescanreduce

problembehavior,dataloss,andcomponentfailureaswellasensurealonger,

trouble-freelifeforyoursystem.Insomecases,Ihave"repaired"ailingsystems

withnothingmorethanapreventivemaintenancesession.Preventive

maintenancealsocanincreaseyoursystem'sresalevaluebecauseitwilllookand

runbetter.

Developingapreventivemaintenanceprogramisimportanttoeveryonewhouses

ormanageslaptops.Thetwomaintypesofpreventivemaintenanceprocedures

arepassiveandactive.

Passivepreventivemaintenanceincludesprecautionarystepsyoucantaketo

protectasystemfromtheenvironment,suchasusingpower-protectiondevices;

ensuringaclean,temperature-controlledenvironment;andpreventingexcessive

vibration.Inotherwords,passivepreventivemaintenancemeanstreatingyour

systemwellandwithcare.

Anactivepreventivemaintenanceprogramincludesperformingproceduresthat

promotealonger,trouble-freelifeforyourlaptop.Thistypeofpreventive

maintenanceprimarilyinvolvestheperiodiccleaningofthesystemandits

components,aswellasperformingbackups,antivirusandantispywarescans,and

othersoftware-relatedprocedures.Thefollowingsectionsdescribebothpassive

andactivepreventivemaintenanceprocedures.



PassivePreventiveMaintenanceProcedures

Passivepreventivemaintenanceinvolvestakingcareofthesystembyproviding

thebestpossibleenvironmentbothphysicalandelectricalforthesystem.Physical

concernsincludeconditionssuchasambienttemperature,thermalstressfrom

powercycling,dustandsmokecontamination,anddisturbancessuchasshock

andvibration.Electricalconcernsincludeitemssuchasstaticelectricity,powerlinenoise(whenthesystemispluggedintoawalloutletorotherexternalpower

source),andradio-frequencyinterference.Eachoftheseenvironmentalconcerns

isdiscussedinthefollowingsubsections.



GeneralSystemCareandHandling

Laptopcomputersareexpensivemachinesbuiltwithsignificantlytighter

tolerancesthantheirdesktopcounterparts.Althoughmostlaptopsaredesignedto

functionreliablyinnormalenvironments,ithelpstousesomecommonsense



88°F

(31°C)



whentransporting,operating,orotherwisehandlingalaptopsystem.Ifyoutreat

thesystemasifitwereaveryexpensivepieceofprecisionelectronicmachinery

(whichittrulyis!),youwillgreatlyminimizethechancesofproblemsoccurring.

Insteadoftellingyouwhatyoushoulddototakecareofyoursystem,itis

perhapseasiertotellyouwhatyoushouldn'tdo.Ioftenobservepeopledoing

thingstotheirlaptopcomputersthatmakemecringe.Whilesomeoftheseare

painfullyobvious,hereisalistofbadthingsyoushouldnotdotoyourlaptop

computer:

Bump,jar,shakeorphysicallypunishthesystem,especiallywhileitis

running.

Dropthesystem.Evenifitisinacarryingcase,manycasesarenotpadded

wellenoughforexcessivelyroughtreatment.

Packalaptopinluggagethatwillbecheckedattheairport,thussubjecting

ittoveryroughhandling.

Placeheavycasesorotherobjectsontopofalaptop(suchasinthe

overheadcompartmentonaplane),evenifitisinacarryingcase.

Storethesystemwherethetemperatureisbelow41°F(5°C)orabove95°F

(35°C).

Operatethecomputeronablanketorothersoftsurfacewherematerial

mightbunchupandcoverthecoolingventsonthesidesorback,whichwill

causethesystemtooverheat.

Operatethecomputerwhileitisstillhalf-insideacarryingcase,whichwill

blockthecoolingventsandcauseoverheating.

Placethesystemcloserthanabout5inches(13cm)fromanyelectrical

devicethatgeneratesastrongmagneticfield,suchaselectricmotors,TVs,

refrigerators,andlargeaudiospeakers.

Operatetwo-wayradiotransmittersincloseproximitytothesystem,which

caninducecurrentsandvoltagescausinglockupsorfailures.

Spillliquidsonthesystem,whichmaycontaminatetheinternalcomponents

and/orcauseashortcircuit.

Placeheavyobjectsonthesystemwiththelidclosedorpackthesystemin

atightlycompressedsuitcaseorbag,whichmayputexcessivepressureon

theLCDpanel.

Placeanobjectbetweenthedisplaylidandkeyboard,whichmaycause

damagewhenthelidisclosed.

PickuporholdthesystembytheLCDpanel,whichmaydamagethedisplay



and/orthehinges.

Scratch,twist,orpushonthesurfaceoftheLCDpanel.

MovethesystemorpullontheACadaptercordwhiletheadapterisplugged

in,whichmaycausetheplugtobreakoffand/ordamagethesocket.

PlugamodemcableintoanEthernetport(andviceversa),whichmay

damagetheconnectors.

Hard-mountthesysteminavehicleoranywherethatitissubjecttostrong

vibration.

Crush,drop,orpressonthecoverofadiskdrivewhileitisremovedfrom

thesystem.

Insertafloppydiskintoafloppydriveatanangleorupsidedown,which

maycauseittojaminthedrive.

Placemorethanonelabelonafloppydisk,whichmightcauseittojamin

thedrive.

TouchthelensontheCD-ROMtraywhenitisopen,whichmaycontaminate

thelensand/orthrowitoutofalignment.

Connecttheinternalmodeminthesystemtoaprivatebranchexchange

(PBX)orotherdigitaltelephonelinethatmaysubjectthemodemto

impropervoltages,thuscausingpermanentdamage.

Forgetyourpasswords.Ifyouforgetasupervisororharddiskpassword,

thereisnoeasywaytoresetit,andyoumayhavetoreplacethe

motherboardorharddisk.

Speakingfromexperience,Icantellyouthatthesystemsyouusewilllastalot

longerifyouavoidanyoftheaforementionedbehavior.



TheOperatingEnvironment

Oddlyenough,oneofthemostoverlookedaspectsofpreventivemaintenanceis

protectingthehardwareandthesizablefinancialinvestmentitrepresentsfrom

environmentalabuse.Computersarerelativelyforgiving,andtheyaregenerally

safeinanenvironmentthatiscomfortableforpeople.Portablecomputers,

however,areoftentossedaroundandtreatedwithnomorerespectthanacheap

calculator.Theresultofthistypeofabusecanbeavarietyofsystemcrashesand

failures.



Temperature,Humidity,andAltitude



Allcomputersaredesignedtooperatewithinspecificrangesoftemperature,

humidity,andaltitude.Exceedingtheallowablerangesplacesstressonthe

systemandcancauseittofailprematurely.Therefore,keepinganeyeonthe

conditionswhereyoubothuseandstoreyourcomputerisimportantforthe

successfuloperationofthesystem.

Temperature,humidity,andaltitudevariationscanleadtoseriousproblems.If

extremetemperaturevariationsoccuroverashortperiod,expansionand

contractioncancausesignaltracesoncircuitboardstocrackandseparate,and

solderjointscanbreak.Extremehumiditycancausecontactsinthesystemto

undergoacceleratedcorrosionorcondensationtoforminthesystemanddisk

drives.Extremelydryconditionscancauseproblemswithstaticelectricity.

Operatingathighaltitudescausesproblemswithcooling(lowerdensityair

rendersthecoolingsystemlesseffective)aswellastheinternal"airbearing"on

whichtheheadsfloatintheharddrivewhileoperating.

Toensurethatyoursystemwillbeoperatedinthetemperature,humidity,and

altituderangesforwhichitwasdesigned,Irecommendyouconsultyoursystem

specificationsfortheenvironmentalrangelimits.Mostmanufacturersprovidedata

aboutthecorrectoperatingtemperaturerangefortheirsystemsintheowner's

manual.Twosetsofspecificationsarenormallylisted:onethatappliestoan

operatingsystemandtheotherforasystempoweredoff.Asanexample,IBM

indicatesthefollowingallowableenvironmentallimitsformostofitsThinkPad

portablesystems:



Maximumaltitudewithoutpressurization



10,000ft.(3,048m)



Temperaturerange(notoperating)



41°110°F(5°43°C)



Maximumtemperaturewhileoperating







Above8,000ft.(2,438m)



Below8,000ft.(2,438m)



Minimumtemperaturewhileoperating



95°F

(35°C)







Notusingthefloppydrive



41°F

(5°C)



Usingthefloppydrive



50°F

(10°C)



Minimumbatterytemperaturewhencharging



Relativehumiditywhileoperating



50°F

(10°C)







Notusingthefloppydrive



8%95%



Usingthefloppydrive



8%80%



Notethatthemaximumallowableambienttemperaturedrops

toonly88°F(31°C)ataltitudesover8,000ft.(2,438m).Thisis

duetothelowerairdensityathighaltitudes,whichreducesthe

efficiencyofthecomputer'scoolingsystem.Alsonotethe

minimumoperatingandnonoperatingtemperatureof41°F

(5°C).Thismeansthatformanyareasofthecountry,itmay

notbewisetoleavealaptopsysteminacarformorethana

shortperiod,ortoshipasystemusingamailorpackagecarrier

duringthewinter.Asyoucanseefromtheprecedingdata,

mostenvironmentalconditionsthatarecomfortableforpeople

arealsogoodforlaptopcomputeruse.



TemperatureAcclimation

Inadditiontothetemperaturelimitsjustdiscussed,itisagood

ideatoavoidrapidchangesintemperatureaswell.Ifarapid

riseintemperatureoccursforexample,whenasystemis

shippedduringthewinterandthenbroughtindoorsyoushould

allowthesystem(andtheharddriveinside)toacclimateto

normalroomtemperaturebeforeturningiton.Inextreme

cases,condensationcanformontheinternalelectronicsaswell

asontheplattersinsidethedrive'sheaddiskassembly(HDA),

whichisdisastrousforthedriveifyouturnitonbeforethe

condensationhasachancetoevaporate.

Mostharddriveshaveafilteredportthatbleedsairintoandout



oftheheaddiskassembly(HDA)sothatmoisturecanenterthe

drive;therefore,aftersomeperiodoftime,itmustbeassumed

thatthehumidityinsideanyharddiskissimilartothehumidity

outsidethedrive.Humiditycanbecomeaseriousproblemifit

isallowedtocondenseandespeciallyifyoupowerupthedrive

whilethiscondensationispresent.Mostharddisk

manufacturershavespecifiedproceduresforacclimatingahard

drivetoanewenvironmentwithdifferenttemperatureand

humidityranges,especiallyforbringingadriveintoawarmer

environmentinwhichcondensationcanform.Thissituation

shouldbeofspecialconcerntousersoflaptopandportable

systems.Ifyouleaveaportablesysteminanautomobiletrunk

duringthewinter,forexample,itcouldbecatastrophictobring

themachineinsideandpoweritupwithoutallowingittimeto

acclimatetothetemperatureindoors.

Thefollowingtext,alongwithTable3.1,aretakenfromthe

factorypackagingthatControlDataCorporation(later

Imprimis,andeventuallySeagate)usedtoshipwithitshard

drives:

Ifyouhavejustreceivedorremovedthisunitfroma

climatewithtemperaturesatorbelow50°F(10°C),donot

openthiscontaineruntilthefollowingconditionsaremet;

otherwise,condensationcouldoccuranddamagetothe

deviceand/ormediamayresult.Placethispackageinthe

operatingenvironmentforthetimedurationaccordingto

thetemperaturechart.

Table3.1.HardDiskDriveEnvironmentalAcclimation

Table

Previous

Climate

Temperature



Acclimation

Time



PreviousClimate

Temperature



Acclimation

Time



+40°F(+4°C)



13hours



0°F(18°C)



18hours



+30°F(1°C)



15hours



10°F(23°C)



20hours



+20°F(7°C)



16hours



20°F(29°C)



22hours



+10°F(12°C)



17hours



30°F(34°C)orless 27hours



AsyoucanseefromTable3.1,youmustplaceaportable

systemwithaharddrivethathasbeenstoredinacolder-thannormalenvironmentintoitsnormaloperatingenvironmentfora

specifiedamountoftimetoallowittoacclimatebeforeyou

poweriton.Manufacturersnormallyadvisethatyouleavethe

systeminitspackingorcarryingcaseuntilitisacclimated.

Removingthesystemfromashippingcartonwhenextremely

coldincreasesthelikelihoodofcondensationforming.Of

course,condensationcanalsoaffectotherpartsofthe

computer,especiallycircuitboardsandconnectors,causing

shortcircuitsorcorrosionthatcannegativelyaffectoperationor

evencausedamage.



StaticElectricity

Staticelectricityorelectrostaticdischarge(ESD)cancause

numerousproblemswithinasystem.Theproblemsusually

appearduringthewintermonthswhenhumidityisloworin

extremelydryclimateswherethehumidityislowyear-round.

Inthesecases,youmightneedtotakespecialprecautionsto

ensurethatyourcomputerisnotdamaged.Seethesection

"ESDProtectionTools,"laterinthischapter,formore

informationonESD.

Staticdischargesoutsideasystem-unitchassisarerarelya

sourceofpermanentproblemswithinthesystem.Usually,the

worstpossibleeffectofastaticdischargetothecase,keyboard,



orevenalocationnearthecomputerisasystemlockup,which

canresultinlostdata.Ifyouknowyouarecarryingacharge,

beforetouchingthekeyboardorsystem,youmighttry

dischargingyourselfbytouchingsomeothermetalobjector

devicetobleedoffsomeofthecharge.Wheneveryouopena

systemunitorhandledevicesremovedfromthesystem,you

mustbemorecarefulwithstatic.



Radio-FrequencyInterference

Radio-frequencyinterference(RFI)iseasilyoverlookedasa

problemfactor.Theinterferenceiscausedbyanysourceof

radiotransmissionsnearacomputersystem.Livingnextdoor

toa50,000-wattcommercialradiostationisonesurewayto

getRFIproblems,butless-powerfulportabletransmitterscan

causeproblems,too.Iknowofmanyinstancesinwhich

cordlesstelephoneshavecausedsporadicrandomkeystrokesto

appear,asthoughaninvisibleentityweretypingonthe

keyboard.IalsohaveseenstrongRFIfromportabletwo-way

radioscauseasystemtolockup.SolutionstoRFIproblemsare

moredifficulttostatebecauseeverycasemustbehandled

differently.Sometimes,simplymovingthesystemeliminates

theproblembecauseradiosignalscanbedirectionalinnature.

Ifyouhaveexternaldevicesattachedtoyourlaptop(suchas

anexternalkeyboard,mouse,ordisplay),sometimesyoumust

investinspeciallyshieldedcablesforthesedevices.Ifthe

keyboardormouseiswireless,thenRFIcanbeespecially

problematic,andtheonlysolutionmaybetotryadifferent

brandormodelthatoperatesonadifferentfrequency.

OnetypeofsolutiontoanRFInoiseproblemwithcablesisto

passthecablethroughatoroidalironcore,adoughnut-shaped

pieceofironplacedaroundacabletosuppressboththe

receptionandtransmissionofelectromagneticinterference

(EMI).You'llnoticethesecoresonmanyofthelaptopexternal

data(USB,FireWire,andsoon)andpowercords.Ifyoucan



isolateanRFInoiseprobleminaparticularcable,youoftencan

solvetheproblembypassingthecablethroughatoroidalcore.

Becausethecablemustpassthroughthecenterholeofthe

core,itoftenisdifficulttoaddatoroidtoacablethatalready

hasendconnectorsinstalled.

RadioShackandotherelectronicssupplystoressellspecial

snap-togethertoroidsdesignedspecificallytobeaddedto

cablesalreadyinuse.Theylooklikeasmallcylinderthathas

beenslicedinhalf.Yousimplylaythecableinthecenterofone

ofthehalvesandsnapthetwohalvestogetheroverthecable.

Thistypeofconstructionmakesaddingthenoise-suppression

featuresofatoroidtovirtuallyanyexistingcableeasy.



Tip

Foracomprehensiveselectionofelectronicsparts,

toolsandothersupplies,Irecommendthefollowing

sources:

AlliedElectronics



www.alliedelec.com



Digi-Key



www.digi-key.com



MouserElectronics



www.mouser.com



NewarkInOne



www.newark.com



RadioShack



www.radioshack.com



Fortoolsonly,Ialsorecommend:

JensenTools







www.jensentools.com



Mostofthesecompaniesalsohavecomprehensive

papercatalogs,whichcanoftenmakegeneral

browsingaswellasfindingwhatyouneedmuch

easier.



Thebest,ifnottheeasiest,waytoeliminateanRFIproblemis

tocorrectitatthesource.Itisunlikelythatyou'llbeableto

convincethecommercialradiostationnearyourofficetoshut

down,butifyouaredealingwithasmallradiotransmitterthat

isgeneratingRFI,sometimesyoucanaddafiltertothe

transmitterthatsuppressesspuriousemissions.Unfortunately,

problemssometimespersistuntilthetransmitteriseither

switchedofformovedsomedistanceawayfromtheaffected

computer.



DustandPollutants

Itshouldbeobviousthatdirt,smoke,dust,andotherpollutants

arebadforyoursystem.Thecoolingfanfoundinmostmodern

laptopsystemscarriesairborneparticlesthroughthesystem,

wheretheycancollectinside.I'mnotsayingthatitisunsafeto

usealaptopsystemoutsideorinanenvironmentthatisn't

absolutelypristine,butIamsayingthatyoushouldconsider

theworkingenvironment.Ifyoutakecareofyoursystem,it

willserveyoulongerandwithfewerproblems.

Ifyoursystemisgoingtoberegularlyusedinanextreme

workingenvironment,youmightwanttoinvestigatesomeof

thespecializedsystemsonthemarketspecificallydesignedfor

useinharshenvironments.Panasonic,forexample,

manufacturesacompletelineofsystemscalledToughbooks,

whicharespeciallydesignedtosurviveunderharshconditions.



DurabilityfeaturesavailableintheToughbooklineincludethe

following:

Magnesiumalloycasewithhandle

Moisture-anddust-resistantLCD,keyboard,andtouchpad

Sealedportandconnectorcovers

Shock-mountedremovableHDDinastainless-steelcase

Vibration-anddrop-shock-resistantdesign

Ruggedhinges

Unfortunately,inmostcases,becauseruggedsystemsmustbe

speciallydesigned,andespeciallybecausetheydon'tsellas

wellasthemainstream,nonruggedmodels,ruggedsystemsare

usuallymorelimitedinoptions,arenotupdatedasfrequently

asmainstreammodels,andingeneralwilloffermuchless

performancethanmainstreammodels.Still,ifamainstream

modelsimplywon'tdofordurability,youshouldconsideroneof

thespeciallydesignedruggedmodels,suchasthePanasonic

Toughbooks.FormoreinformationontheToughbooklineof

laptopsystems,visitPanasonicat

www.panasonic.com/toughbook.



TipsforTransportingYourSystem

Whenyouaretransportingalaptopcomputer,Irecommendyou

considerthefollowingguidelinesinordertoprotectthesystem:

Removeallfloppydiskand/orCD/DVDdiscmediafromthe



Tài liệu bạn tìm kiếm đã sẵn sàng tải về

Chapter 3.  System Maintenance and Assembly

Tải bản đầy đủ ngay(0 tr)

×
x