Lenovo T550 Technical Information Page 44

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No-beepsymptoms
Table4.No-beepsymptoms
Symptomorerror
FRUoraction,insequence
Nobeep,system-statusindicatoron,LCDblank,andno
POST.
1.Ensurethateveryconnectorisconnectedtightly
andcorrectly.
2.Systemboard
Nobeep,system-statusindicatoron,andLCDblank
duringPOST.
Systemboard
Thepower-onpasswordpromptappears.Apower-onpasswordorasupervisorpasswordis
set.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.
LenovowillnotprovidewarrantyreplacementiftheLCDiswithinspecificationsbecausewecannot
guaranteethatanyreplacementLCDwillhavezeropixeldefects.
OnepixelconsistsofR,G,Bsub-pixels.
Table5.LCD-relatedsymptoms
Symptomorerror
FRUoraction,insequence
Nobeep,power-onindicatoron,andablankLCDduring
POST.
Systemboard
LCDbacklightnotworking.
LCDtoodark.
LCDbrightnesscannotbeadjusted.
LCDcontrastcannotbeadjusted.
1.ReseattheLCDconnectors.
2.LCDassembly
3.Systemboard
LCDscreenunreadable.
Charactersmissingpixels.
Screenabnormal.
Wrongcolordisplayed.
1.Seeimportantnotefor“LCD-relatedsymptoms.
2.ReseatallLCDconnectors.
3.LCDassembly
4.Systemboard
HorizontalorverticallinesdisplayedonLCD.LCDassembly
Intermittentproblems
Intermittentsystemhangproblemscanbeduetoavarietyofcausesthathavenothingtodowithahardware
defect,suchascosmicradiation,electrostaticdischarge,orsoftwareerrors.FRUreplacementshouldbe
consideredonlywhenaproblemrecurs.
Whenanalyzinganintermittentproblem,dothefollowing:
1.Runthediagnostictestforthesystemboardinloopmodeatleast10times.
2.Ifnoerrorisdetected,donotreplaceanyFRUs.
38HardwareMaintenanceManual
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