Contents
Aboutthismanual...........iii
Chapter1.Safetyinformation......1
Generalsafety................1
Electricalsafety...............2
Safetyinspectionguide............3
Handlingdevicesthataresensitivetoelectrostatic
discharge..................3
Groundingrequirements............4
Safetynotices(multilingualtranslations)......5
Lasercompliancestatement(multilingual
translations)................17
Chapter2.Importantservice
information..............23
StrategyforreplacingFRUs.........23
Strategyforreplacingaharddiskdrive...23
Importantnoticeforreplacingasystem
board................24
Howtouseerrormessage........24
StrategyforreplacingFRUsforCTO,CMV,and
GAV...................25
Productdenition............25
FRUidenticationforCTO,CMV,andGAV
products...............25
Chapter3.Generalcheckout.....27
Whattodorst..............28
Checkoutguide..............29
DiagnosticsusingPC-DoctorforDOS....29
LenovoThinkVantageToolbox.......31
FRUtests...............33
Powersystemcheckout...........34
Checkingtheacpoweradapter......34
Checkingoperationalcharging......34
Checkingthebatterypack........35
Checkingthebackupbattery.......35
Chapter4.Relatedservice
information..............37
RestoringthefactorycontentsbyusingRecovery
DiscSet.................37
Passwords................38
Power-onpassword...........38
Hard-diskpassword...........38
Supervisorpassword..........39
Howtoremovethepower-onpassword...39
Howtoremovethehard-diskpassword...39
Powermanagement............41
Screenblankmode...........41
Sleep(standby)mode..........41
Hibernationmode...........41
Symptom-to-FRUindex...........43
Numericerrorcodes..........43
Errormessages............45
Beepsymptoms............46
No-beepsymptoms...........46
LCD-relatedsymptoms.........46
Intermittentproblems..........48
Undeterminedproblems.........48
Chapter5.Statusindicators.....49
Chapter6.Fnkeycombinations...53
Chapter7.FRUreplacement
notices................57
Screwnotices...............57
Retainingserialnumbers...........58
Restoringtheserialnumberofthesystem
unit.................58
RetainingtheUUID...........59
ReadingorwritingtheECAinformation...59
Chapter8.Removingandreplacinga
FRU..................61
BeforeservicingThinkPadT420andT420i...62
1010Batterypack.............63
1020ExpressCardblankbezel........64
1030SerialUltrabayEnhanceddeviceortravel
bezel..................65
1040Harddiskdrive(HDD)andsolidstatedrive
(SSD)..................66
1050DIMMslotcover............69
1060DIMM(intheslotontheundersideofthe
computer)................70
1070PCIExpressMiniCardforwirelessWAN..71
1080Keyboard..............73
1090DIMM(intheslotunderthekeyboard)...77
1100Backupbattery............79
1110PCIExpressMiniCardforwirelessLAN..81
1120Keyboardbezelassembly,FPCcable,and
Bluethoothdaughtercard..........83
1130SmartCard..............88
1140Modemdaughtercard(MDC).......90
1150Speakerassembly...........91
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