User's Manual

Note:Ifthebatterypackbecomeshot,itmaynotbeabletocharge.Removeitfromthecomputerandleave
itatroomtemperatureforawhile.Afteritcoolsdown,reinstallandrechargeit.
Tocheckthebatterypack,dothefollowing:
1.Poweroffthecomputer.
2.Removethebatterypackandmeasurethevoltagebetweenbatteryterminals1(+)and7(-).Seethe
followinggure:
Terminal
Voltage(Vdc)
1+0to+12.6
7
Ground(-)
1(+)
2(+)
3
4
5
6(-)
7(-)
3.Ifthevoltageislessthan+11.0Vdc,thebatterypackhasbeendischarged.
Note:Rechargingwilltakeatleast3hours,eveniftheindicatordoesnotturnon.
Ifthevoltageisstilllessthan+11.0Vdcafterrecharging,replacethebattery.
4.Ifthevoltageismorethan+11.0Vdc,measuretheresistancebetweenbatteryterminals5and7.
Theresistancemustbe4to30KΩ.Iftheresistanceisnotcorrect,replacethebatterypack.Ifthe
resistanceiscorrect,replacethesystemboard.
Checkingthebackupbattery
Dothefollowing:
1.Poweroffthecomputer,andunplugtheacadapterfromit.
2.T urnthecomputerupsidedown.
3.Removethebatterypack(see1010Batterypack).
4.Removethebackupbattery(see1120Backupbattery).
5.Measurethevoltageofthebackupbattery.Seethefollowinggure.
Wire
Voltage(Vdc)
Red+2.5to+3.2
Black
Ground
Red(+)
Black(-)
•Ifthevoltageiscorrect,replacethesystemboard.
•Ifthevoltageisnotcorrect,replacethebackupbattery.
•Ifthebackupbatterydischargesquicklyafterreplacement,replacethesystemboard.
34ThinkPadT520,T520i,andW520HardwareMaintenanceManual