Contents
Aboutthismanual..........iii
Chapter1.Safetyinformation......1
Generalsafety................1
Electricalsafety...............2
Safetyinspectionguide............3
Handlingdevicesthataresensitivetoelectrostatic
discharge..................3
Groundingrequirements............4
Safetynotices(multilingualtranslations)......4
Lasercompliancestatement(multilingual
translations)................24
Chapter2.Importantservice
information..............31
StrategyforreplacingFRUs.........31
Strategyforreplacingaharddiskdrive...32
Importantnoticeforreplacingasystem
board................32
Howtouseerrormessage........32
StrategyforreplacingFRUsforCTO,CMV,and
GAV...................32
Productdenition............32
FRUidenticationforCTO,CMV,andGAV
products...............33
Chapter3.Generalcheckout.....35
Whattodorst..............35
Checkoutguide..............36
DiagnosticsusingPC-DoctorforDOS....36
LenovoThinkVantageToolbox.......39
FRUtests...............39
Powersystemcheckout...........41
Checkingtheacpoweradapter......41
Checkingoperationalcharging......42
Checkingthebatterypack........42
Checkingthebackupbattery.......42
Chapter4.Relatedservice
information..............45
RestoringthefactorycontentsbyusingProduct
Recoverydiscs..............45
RestoringthefactorycontentsbyusingRecovery
DiscSet.................45
Passwords................47
Power-onpassword...........47
Harddiskpassword...........47
Supervisorpassword..........47
Howtoremovethepower-onpassword...47
Howtoremovetheharddiskpassword...48
Powermanagement............48
Screenblankmode...........48
Sleep(standby)mode..........49
Hibernationmode...........49
Symptom-to-FRUindex...........50
Numericerrorcodes..........51
Errormessages............52
Beepsymptoms............52
No-beepsymptoms...........53
LCD-relatedsymptoms.........53
Intermittentproblems..........54
Undeterminedproblems.........54
Chapter5.Statusindicators.....55
Chapter6.Fnkeycombinations...59
Chapter7.FRUreplacement
notices................61
Screwnotices...............61
Retainingserialnumbers...........62
Restoringtheserialnumberofthesystem
unit.................62
RetainingtheUUID...........62
ReadingorwritingtheECAinformation...63
Chapter8.Removingandreplacinga
FRU..................65
BeforeservicingThinkPadT420sandT420si
models..................65
1010Batterypack.............66
1020SerialUltrabaySlimdeviceortravelbezel..67
1030Solidstatedrive(SSD)orharddiskdrive
(HDD)..................68
1040DIMM................70
1050PCIExpressMiniCardforwirelessLAN..72
1060PCIExpressMiniCardforwirelessWAN..75
10704–in–1mediacardreader........77
1080Keyboard..............78
1090Backupbattery............81
1100Palmrestwithngerprintreader,smartcard
reader,andspeaker.............82
1110LCDunit...............86
1120DC-insubcard............88
1130Bluetoothdaughtercard(BDC-3.0)....89
1140Bluetooth-wirelessradioswitchFPC....89
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