Lenovo ThinkPad T420 User Manual

Ifyourcomputeriscompletelyunresponsive(youcannotusetheUltraNavpointingdeviceorthekeyboard),
dothefollowingsteps:
1.Pushandholdthepowerswitchuntilthemachineturnsoff.Afterthecomputeristurnedoff,restartby
pressingthepowerswitch.Ifthemachinedoesnotturnon,continuetostep2.
Note:Donotremovethebatteryandacpowertoresetthecomputer.
2.Whilethemachineisturnedoff,removeallpowersourcesfromthecomputer(batteryandacpower).
Holddownthepowerbuttonfor10seconds.Plugintheacpowerwhilekeepingthebatteryoutofthe
computer.Ifthecomputerdoesnotturnbackon,continuetostep3.
Note:OncethecomputerstartsupandentersWindows,usethepropershutdownproceduretoturn
thecomputeroff.Oncethemachineisoff,reattachthebatteryandrestartthecomputer.Ifthe
computerdoesnotstartwiththebatteryreattached,removethebatteryandagainstartwithstep2.If
thecomputerstartswithacpowerbutdoesnotstartwhenthebatteryisattached,calltheCustomer
SupportCenterforsupport.
3.Whilethemachineisoff,removeallsourcesofpowerfromthemachine(batteryandacpower).Remove
allexternaldevicesthatareattachedtoyourcomputer(keyboard,mouse,printer,scanner,etc.).Repeat
step2.Ifstep2isunsuccessful,continuetostep4.
Note:Thefollowingstepsinvolveremovingstaticsensitivecomponentsfromyourcomputer.Please
makesurethatyouareproperlygroundedandremoveallsourcesofpowerattachedtothecomputer.
IfyouareuncomfortableorunsureaboutremovingcomponentspleasecalltheCustomerSupport
Centerforassistance.
4.Whilethecomputerisoff,removeallsourcesofpowerandexternalhardware.Refertotheprocedurein
“Replacingmemory”onpage123onhowtoremoveandreseatthememorymodules.Removeany
non-originalmemorymoduleaddedtoyourcomputer.Afterremovingtheextramemorymoduleand
reseatingtheoriginalmemorymodule,repeatstep2.Ifthecomputerstilldoesnotturnon,consultthe
user'sreferenceguideforothercustomer-replaceablecomponentsthatareattachedtoyourcomputer
Ifthecomputerstilldoesnotstartup,calltheCustomerSupportCenterandaCustomerSupportSpecialist
willassistyou.
Spillsonthekeyboard
Withamobilecomputer,thereareincreasedchancesofspillingliquidsonthekeyboard.Becausemost
liquidsconductelectricity,liquidspilledonthekeyboardcouldcreatenumerousshortcircuits,potentially
causingirreparabledamagetoyourcomputer.
Ifyouspillsomethingonyourcomputer:
Attention:Besurethatnoliquidcreatesashortcircuitbetweenyouandtheacpoweradapter(ifinuse).
Althoughyoumightlosesomedataorworkbyturningoffthecomputerimmediately,leavingthecomputer
onmightmakeyourcomputerunusable.
1.Carefullyunplugtheacpoweradapterimmediately.
2.Turnoffthecomputerimmediately.Ifthecomputerdoesnotturnoff,removethebattery.Themore
quicklyyoustopthecurrentfrompassingthroughthecomputerthemorelikelyyouwillreducedamage
fromshortcircuits.
3.Waituntilyouarecertainthatalltheliquidisdrybeforeturningonyourcomputer.
Note:Ifyouwanttoreplaceyourkeyboard,youcanpurchaseanewone.
Errormessages
•Message:0176:SystemSecurity-TheSystemhasbeentamperedwith.
204UserGuide

Lenovo ThinkPad T420 Specifications

General

Processor cache	3 MB
Processor front side bus	1333 MHz
Number of processors supported	1
Display diagonal	14 \
Display resolution	1366 x 768 pixels
AC adapter power	65 W
Indication light	Yes
Infrared data port	No
Number of speakers	2
Maximum internal memory	8 GB
Speaker power	1 W
Battery voltage	10.8 V
HDD speed	7200 RPM
HDD capacity	320 GB
HDD interface	SATA

Weight and Dimensions

Depth	337 mm
Height	21.2 mm
Height (imperial)	0.83 \