ThinkPad T420s - Page 71

MTMonrearlabel:
TTTT-CTOS/NSSSSSSS
ProductIDonrearlabel:
TTTT-MMM(UsethisnumberwhensettingSerial
Number)
Intheexample,theSerialNumbertobeinputis“1STTTTMMMSSSSSSS”.
RetainingtheUUID
TheUniversallyUniqueIdentifier(UUID)isa128-bitnumberuniquelyassignedtoyourcomputerat
productionandstoredintheEEPROMofyoursystemboard.Thealgorithmthatgeneratesthenumberis
designedtoprovideuniqueIDsuntiltheyearA.D.3400.Notwocomputersintheworldhavethesame
number.
Whenyoureplacethesystemboard,youmustsettheUUIDonthenewsystemboardasfollows:
1.InstalltheLENOVOThinkPadHardwareMaintenanceDisketteVersion1.76orlater,andrestartthe
computer.
2.Fromthemainmenu,select4.AssignUUID.AnewUUIDiscreatedandwritten.IfavalidUUIDalready
exists,itisnotoverwritten.
ReadingorwritingtheECAinformation
InformationonEngineeringChangeAnnouncements(ECA)arestoredintheEEPROMofthesystemboard.
TheelectronicstorageofthisinformationsimplifiestheproceduretocheckiftheECAhasbeenpreviously
appliedtoamachine.ThemachinedoesnotneedtobedisassembledtocheckfortheECAapplication.
TocheckwhatECAshavebeenpreviouslyappliedtothemachine,usetheECAInformationRead/Write
functionontheLENOVOThinkPadHardwareMaintenanceDisketteVersion1.76orlater.
1.InserttheLENOVOThinkPadHardwareMaintenanceDisketteVersion1.76orlater,andrestartthe
computer.
2.Fromthemainmenu,select6.SetECAInformation.
3.ToreadECAinformation,select2.ReadECA/reworknumberfromEEPROMandfollowthe
instruction.
4.Toreadboxbuilddate,select5.ReadboxbuilddatefromEEPROM,andfollowtheinstructionon
thescreen.
AfteranECAhasbeenappliedtothemachine,theEEPROMmustbeupdatedtoreflecttheECA's
application.UsetheLENOVOThinkPadHardwareMaintenanceDisketteVersion1.76orlatertoupdatethe
EEPROM.
Note:OnlytheECAnumberisstoredintheEEPROM.ThemachinetypeoftheECAisassumedbethe
sameasthemachinetypeofthemachinethathadtheECAappliedtoit.
1.InserttheLENOVOThinkPadHardwareMaintenanceDisketteVersion1.76orlater,andrestartthe
computer.
2.Fromthemainmenu,select6.SetECAInformation.
3.TowriteECAinformation,select1.WriteECA/reworknumberfromEEPROM,andfollowthe
instruction.
4.Towriteboxbuilddate,select4.WriteboxbuilddatefromEEPROM,andfollowtheinstructionon
thescreen.
Ifthesystemboardisbeingreplaced,trytoreadtheECAinformationfromtheoldsystemboardandtransfer
theinformationtothenewsystem.Ifthesystemboardisinoperable,thiswillnotbepossible.
Chapter7.FRUreplacementnotices65