ThinkPad E550 - Chapter 5. Status Indicators

LCD-relatedsymptoms
Important:TheTFTLCDforthenotebookcomputercontainsmanythin-filmtransistors(TFTs).The
presenceofasmallnumberofdotsthataremissing,discolored,oralwayslightedischaracteristicofTFT
LCDtechnology,butexcessivepixelproblemscancauseviewingconcerns.
IftheLCDyouareservicinghastwoorlessvisibledefectivepixels,itshouldnotbeconsideredfaulty.
However,iftheLCDhasthreeormorevisibledefectivepixels,itwillbedeemedasdefectivebyLenovoand
itshouldbereplaced.
Notes:
•ThispolicyappliestoallThinkPadNotebookspurchasedon1January,2008orlater.
•LenovowillnotprovidewarrantyreplacementiftheLCDiswithinspecificationsbecausewecannot
guaranteethatanyreplacementLCDwillhavezeropixeldefects.
•OnepixelconsistsofR,G,Bsub-pixels.
Table6.LCD-relatedsymptoms
Symptomorerror
FRUoraction,insequence
Nobeep,power-onindicatoron,andablankLCDduring
POST.
Replacethesystemboard.
•LCDbacklightnotworking.
•LCDtoodark.
•LCDbrightnesscannotbeadjusted.
•LCDcontrastcannotbeadjusted.
1.ReseattheLCDconnectors.
2.ReplacetheLCDassembly.
3.Replacethesystemboard.
•LCDscreenunreadable.
•Charactersmissingpixels.
•Screenabnormal.
•Wrongcolordisplayed.
1.Seeimportantnotefor“LCD-relatedsymptoms.”
2.ReseatallLCDconnectors.
3.ReplacetheLCDassembly.
4.Replacethesystemboard.
HorizontalorverticallinesdisplayedonLCD.ReplacetheLCDassembly.
Intermittentproblems
Intermittentsystemhangproblemscanbeduetoavarietyofcausesthathavenothingtodowithahardware
defect,suchascosmicradiation,ESD,orsoftwareerrors.FRUreplacementshouldbeconsideredonly
whenaproblemrecurs.
Whenanalyzinganintermittentproblem,dothefollowing:
1.Runthediagnostictestforthesystemboardinloopmodeatleast10times.
2.Ifnoerrorisdetected,donotreplaceanyFRUs.
3.Ifanyerrorisdetected,replacetheFRUshownbytheFRUcode.Rerunthetesttoverifythatno
moreerrorsexist.
Undeterminedproblems
Ifthediagnostictestsdidnotidentifythedevicethathasfailed,ifwrongdevicesareinstalled,orifthe
systemsimplyisnotoperating,followtheseprocedurestoisolatethefailingFRU(donotisolateFRUs
thathavenodefects).
Verifythatallattacheddevicesaresupportedbythecomputer.
Verifythatthepowersupplybeingusedatthetimeofthefailureisoperatingcorrectly.(See“Powersystem
checkout”onpage33
)
1.Turnoffthecomputer.
Chapter4.Relatedserviceinformation47