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 R50 R51 X30 X31

P/N: 02K7078 08K8050 92K0986


Package : 1 pcs of CMOS battery