Cause:
Like any battery the computer CMOS battery can fail or lose its charge.

Solution:
If your computer is losing its time or date settings�� or you are receiving a message CMOS Read Error�� CMOS checksum error�� or CMOS Battery Failure�� first try leaving the computer on for 24-hours. In some cases this can charge the battery and resolve your issue. This often resolves CMOS battery related issues when a computer has been left off for several months. 


Compatible with the models :

IBM Thinkpad 560 Series: 560, 560E, 560X, 560Z

IBM Thinkpad 570 Series: 570, 570E, 570X, 570Z

IBM ThinkPad A Series: A20, A20P, A20M, A21, A21E, A21M, A21P, A22, A22M, A22P, A23, A30, A30P, A31P

IBM ThinkPad T Series: T20, T21, T22, T23, T30, T40, T41, T42, T43, T60

IBM ThinkPad R Series: R40, R50, R50e, R50p, R51

IBM ThinkPad X Series: X30, X31, X32

IBM xSeries: 300, 400


Package : 1 pcs of CMOS battery