ThinkPad T420s - Page 61

Table4.Beepsymptoms(continued)
Symptomorerror
FRUoraction,insequence
Twoormorebeeps,oracontinuousbeep.Operating
systemstartssuccessfully.
Ifamini-PCIEthernetcardisinstalled,confirmthatAlert
OnLAN2inThinkPadSetupisdisabled.
Threeshortbeeps,pause,threemoreshortbeeps,and
oneshortbeep.
Oneshortbeep,pause,threeshortbeeps,pause,three
moreshortbeeps,andoneshortbeep.
1.DIMM.
2.Systemboard
Onlythecursorappears.
Reinstalltheoperatingsystem.
Fourcyclesoffourshortbeepsandablankscreen.
Systemboard(securitychip)
Fiveshortbeepsandablankscreen.
Systemboard
No-beepsymptoms
Table5.No-beepsymptoms
Symptomorerror
FRUoraction,insequence
Nobeep,power-onindicatoron,LCDblank,andno
POST.
1.Makesurethateveryconnectorisconnected
tightlyandcorrectly.
2.DIMM.
3.Systemboard.
Nobeep,power-onindicatoron,andLCDblankduring
POST.
1.ReseatDIMM.
2.Systemboard.
Thepower-onpasswordpromptappears.Apower-onpasswordorasupervisorpasswordisset.
TypethepasswordandpressEnter.
Thehard-diskpasswordpromptappears.Ahard-diskpasswordisset.Typethepasswordand
pressEnter.
LCD-relatedsymptoms
Important:TheTFTLCDforthenotebookcomputercontainsmanythin-filmtransistors(TFTs).The
presenceofasmallnumberofdotsthataremissing,discolored,oralwayslightedischaracteristicofTFT
LCDtechnology,butexcessivepixelproblemscancauseviewingconcerns.IftheLCDyouareservicinghas
twoorlessvisibledefectivepixels,itshouldnotbeconsideredfaulty.However,iftheLCDhasthreeormore
visibledefectivepixels,itwillbedeemedasdefectivebyLenovoanditshouldbereplaced.
Notes:
•ThispolicyappliestoallThinkPadNotebookspurchasedon1January,2008orlater.
•LenovowillnotprovidereplacementiftheLCDiswithinspecificationaswecannotguaranteethat
anyreplacementLCDwillhavezeropixeldefects.
•OnepixelconsistsofR,G,Bsub-pixels.
Table6.LCD-relatedsymptoms
Symptomorerror
FRUoraction,insequence
Nobeep,power-onindicatoron,andablankLCDduring
POST.
Systemboard.
•LCDbacklightnotworking.
•LCDtoodark.
•LCDbrightnesscannotbeadjusted.
•LCDcontrastcannotbeadjusted.
1.ReseattheLCDconnectors.
2.LCDassembly.
3.Systemboard.
Chapter4.Relatedserviceinformation55