Lenovo N21 Chromebook Owner's manual

HardwareMaintenanceManual
LenovoN21Chromebook

HardwareMaintenanceManual
LenovoN21Chromebook

FirstEdition(March2015)
©CopyrightLenovo2015.

Contents
Chapter1.Safetyinformation.....1
Generalsafety...............1
Electricalsafety..............1
Safetyinsectionguide...........2
Handlingdevicesthataresensitivetoelectrostatic
discharge.................3
Groundingrequirements...........4
Safetynotices(multilingualtranslations).....4
Chapter2.eneralcheckout.....19
Whattodofirst..............19
Checkingtheacoweradater........20
Chapter3.IdetifyingFRUs(CRUs)..21
AllFRUs(CRUs)forLenovoN21Chromebook..21
LenovoartnumbersofrelacementFRUsor
CRUs..................25
Chapter4.RemovingaFRUorCRU.27
Generalguidelines.............27
Removetheuercaseandthebattery.....27
Removetheseakers............31
RemovetheI/Oboard............32
RemovetheWLAN&Bluetoothcombomodule..33
RemovetheLCDmodule..........34
Removethethermalmodule,thesystemboard
andtheDC-incable............35
DisassembletheLCDmodule.........37
RemovetheLCDbezel..........37
RemovetheLCDanel.........39
Removethecameraboard,thecameracover
andtheEDPcable...........40
RemovethehingesandtheWLANantennas.42
AppendixA.Features,controls,and
connectors..............45
AppendixB.Specifications......47
AppendixC.Lenovopartnumbersof
screwsusedonN21Chromebook..49
AppendixD.Lenovopartnumbersof
acadaptersandpowercords....51
AppendixE.Labellocations......53
Trademarks................lv
©CoyrightLenovo2015iii

ivHardwareMaintenanceManual

Chapter1.Safetyinformation
Thischaterresentsthefollowingsafetyinformationthatyouneedtobefamiliarwithbeforeyouservicea
Lenovonotebookcomuter.
eneralsafety
Followtheserulestoensuregeneralsafety:
•Observegoodhousekeeingintheareaofthemachinesduringandaftermaintenance.
•Whenliftinganyheavyobject:
1.Makesurethatyoucanstandsafelywithoutsliing.
2.Distributetheweightoftheobjectequallybetweenyourfeet.
3.Useaslowliftingforce.Nevermovesuddenlyortwistwhenyouattemttolift.
4.Liftbystandingorbyushinguwithyourlegmuscles;thisactionremovesthestrainfromthe
musclesinyourback.Donotattempttoliftanyobjectthatweighsmorethan16kg(35lb)orthat
youthinkistooheavyforyou.
•Donoterformanyactionthatcauseshazardstothecustomer,orthatmakestheequimentunsafe.
•Beforeyoustartthemachine,makesurethatotherservicetechniciansandthecustomer'sersonnelare
notinahazardousosition.
•Placeremovedcoversandotherartsinasafelace,awayfromallersonnel,whileyouareservicing
themachine.
•Keeyourtoolcaseawayfromwalkareassothatothereolewillnottrioverit.
•Donotwearlooseclothingthatcanbetraedinthemovingartsofamachine.Makesurethatyour
sleevesarefastenedorrolleduaboveyourelbows.Ifyourhairislong,fastenit.
•Inserttheendsofyournecktieorscarfinsideclothingorfastenitwithanon-conductivecli,about8
centimeters(3inches)fromtheend.
•Donotwearjewelry,chains,metal-frameeyeglasses,ormetalfastenersforyourclothing.
Attention:Metalobjectsaregoodelectricalconductors.
•Wearsafetyglasseswhenyouarehammering,drilling,soldering,cuttingwire,attachingsrings,using
solvents,orworkinginanyotherconditionsthatmightbehazardoustoyoureyes.
•Afterservice,reinstallallsafetyshields,guards,labels,andgroundwires.Relaceanysafetydevice
thatiswornordefective.
•Reinstallallcoverscorrectlybeforereturningthemachinetothecustomer.
•Fanlouversonthemachineheltoreventoverheatingofinternalcomonents.Donotobstructfan
louversorcoverthemwithlabelsorstickers.
Electricalsafety
Observethefollowingruleswhenworkingonelectricalequiment.
Important:Useonlyarovedtoolsandtestequiment.Somehandtoolshavehandlescoveredwithasoft
materialthatdoesnotinsulateyouwhenworkingwithliveelectricalcurrents.Manycustomershave,near
theirequiment,rubberfloormatsthatcontainsmallconductivefiberstodecreaseelectrostaticdischarges.
Donotusethistyeofmattorotectyourselffromelectricalshock.
•Findtheroomemergencyower-off(EPO)switch,disconnectingswitch,orelectricaloutlet.Ifanelectrical
accidentoccurs,youcanthenoeratetheswitchorunlugtheowercordquickly.
•Donotworkaloneunderhazardousconditionsornearequimentthathashazardousvoltages.
•Disconnectallowerbefore:
–Performingamechanicalinsection
–Workingnearowersulies
©CoyrightLenovo20151

–Removingorinstallingmainunits
•Beforeyoustarttoworkonthemachine,unlugtheowercord.Ifyoucannotunlugit,askthecustomer
toower-offthewallboxthatsuliesowertothemachine,andtolockthewallboxintheoffosition.
•Ifyouneedtoworkonamachinethathasexposeelectricalcircuits,observethefollowingrecautions:
–Ensurethatanothererson,familiarwiththeower-offcontrols,isnearyou.
Attention:Anotherersonmustbetheretoswitchofftheower,ifnecessary.
–Useonlyonehandwhenworkingwithowered-onelectricalequiment;keetheotherhandinyour
ocketorbehindyourback.
Attention:Anelectricalshockcanoccuronlywhenthereisacomletecircuit.Byobservingtheabove
rule,youmayreventacurrentfromassingthroughyourbody.
–Whenusingtesters,setthecontrolscorrectlyandusethearovedrobeleadsandaccessoriesfor
thattester.
–Standonsuitablerubbermats(obtainedlocally,ifnecessary)toinsulateyoufromgroundssuchas
metalfloorstrisandmachineframes.
Observethesecialsafetyrecautionswhenyouworkwithveryhighvoltages;Instructionsforthese
recautionsareinthesafetysectionsofmaintenanceinformation.Useextremecarewhenmeasuring
highvoltages.
•Regularlyinsectandmaintainyourelectricalhandtoolsforsafeoerationalcondition.
•Donotusewornorbrokentoolsandtesters.
•Neverassumethatowerhasbeendisconnectedfromacircuit.First,checkthatithasbeenoweredoff.
•Alwayslookcarefullyforossiblehazardsinyourworkarea.Examlesofthesehazardsaremoistfloors,
non-groundedowerextensioncables,owersurges,andmissingsafetygrounds.
•Donottouchliveelectricalcircuitswiththereflectivesurfaceofalasticdentalmirror.Thesurfaceis
conductive;suchtouchingcancauseersonalinjuryandmachinedamage.
•Donotservicethefollowingartswiththepoweronwhentheyareremovedfromtheirnormaloerating
lacesinamachine:
–Powersulyunits
–Pums
–Blowersandfans
–Motorgenerators
–Similarunitsaslistedabove
Thisracticeensurescorrectgroundingoftheunits.
•Ifanelectricalaccidentoccurs:
–Usecaution;donotbecomeavictimyourself.
–Switchoffower.
–Sendanotherersontogetmedicalaid.
Safetyinspectionguide
Theuroseofthisinsectionguideistoassistyouinidentifyingotentiallyunsafeconditions.Aseach
machinewasdesignedandbuilt,requiredsafetyitemswereinstalledtorotectusersandservicetechnicians
frominjury.Thisguideaddressesonlythoseitems.Youshouldusegoodjudgmenttoidentifyotential
safetyhazardsduetoattachmentofnon-Lenovofeaturesorotionsnotcoveredbythisinsectionguide.
Ifanyunsafeconditionsareresent,youmustdeterminehowserioustheaarenthazardcouldbeand
whetheryoucancontinuewithoutfirstcorrectingtheroblem.
Considertheseconditionsandthesafetyhazardstheyresent:
•Electricalhazards,eseciallyrimaryower(rimaryvoltageontheframecancauseseriousorfatal
electricalshock)
•Exlosivehazards,suchasadamagedcathoderaytube(CRT)faceorabulgingcaacitor
•Mechanicalhazards,suchaslooseormissinghardware
2HardwareMaintenanceManual

Todeterminewhetherthereareanyotentiallyunsafeconditions,usethefollowingchecklistatthebeginning
ofeveryservicetask.Beginthecheckswiththeoweroff,andtheowercorddisconnected.
Checklist:
1.Checkexteriorcoversfordamage(loose,broken,orsharedges).
2.Poweroffthecomuter.Disconnecttheowercord.
3.Checktheowercordfor:
a.Athird-wiregroundconnectoringoodcondition.Useametertomeasurethird-wireground
continuityfor0.1ohmorlessbetweentheexternalgroundinandtheframeground.
b.Theowercordshouldbetheauthorizedtyesecifiedforyourcomuter.Goto:
htt://www.lenovo.com/servicearts-looku
c.Insulationmustnotbefrayedorworn.
4.Checkforcrackedorbulgingbatteries.
5.Removethecover.
6.Checkforanyobviousnon-Lenovoalterations.Usegoodjudgmentastothesafetyofanynon-Lenovo
alterations.
7.Checkinsidetheunitforanyobviousunsafeconditions,suchasmetalfilings,contamination,wateror
otherliquids,orsignsoffireorsmokedamage.
8.Checkforworn,frayed,orinchedcables.
9.Checkthattheower-sulycoverfasteners(screwsorrivets)havenotbeenremovedortameredwith.
Handlingdevicesthataresensitivetoelectrostaticdischarge
Anycomuterartcontainingtransistorsorintegratedcircuits(ICs)shouldbeconsideredsensitiveto
electrostaticdischarge(ESD).ESDdamagecanoccurwhenthereisadifferenceinchargebetweenobjects.
ProtectagainstESDdamagebyequalizingthechargesothatthemachine,theart,theworkmat,andthe
ersonhandlingtheartareallatthesamecharge.
Notes:
1.Useroduct-secificESDrocedureswhentheyexceedtherequirementsnotedhere.
2.MakesurethattheESDrotectivedevicesyouusehavebeencertified(ISO9000)asfullyeffective.
WhenhandlingESD-sensitivearts:
•Keetheartsinrotectiveackagesuntiltheyareinsertedintotheroduct.
•Avoidcontactwithothereole.
•Wearagroundedwriststraagainstyourskintoeliminatestaticonyourbody.
•Preventtheartfromtouchingyourclothing.Mostclothingisinsulativeandretainsachargeeven
whenyouarewearingawriststra.
•Useagroundedworkmattorovideastatic-freeworksurface.Thematiseseciallyusefulwhen
handlingESD-sensitivedevices.
•Selectagroundingsystem,suchasthoselistedbelow,toroviderotectionthatmeetsthesecific
servicerequirement.
Note:TheuseofagroundingsystemtoguardagainstESDdamageisdesirablebutnotnecessary.
–AttachtheESDgroundclitoanyframeground,groundbraid,orgreen-wireground.
–Whenworkingonadouble-insulatedorbattery-oeratedsystem,useanESDcommongroundor
referenceoint.Y oucanusecoaxorconnector-outsideshellsonthesesystems.
–Usetheroundgroundrongoftheaclugonac-oeratedcomuters.
Chater1.Safetyinformation3

roundingrequirements
Electricalgroundingofthecomuterisrequiredforoeratorsafetyandcorrectsystemfunction.Proer
groundingoftheelectricaloutletcanbeverifiedbyacertifiedelectrician.
Safetynotices(multilingualtranslations)
Thesafetynoticesinthissectionarerovidedinthefollowinglanguages:
•English
•Arabic
•BrazilianPortuguese
•French
•German
•Hebrew
•Jaanese
•Korean
•Sanish
•T raditionalChinese
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