|As a person who has been around electronics since Junior High school, I can tell you this:|
Stuart does not know what he is talking about.
First, there is no "coin" battery "on" the motherboard of a Thinkpad
Second, if there was, your "fingers" would absolutely, positively not discharge that battery
(or for that matter, negatively discharge it, ha ha)
Third, go to the IBM site, go to support, and find and download your "hardware maintenance" manual.
That manual will define the error codes, and it will tell you how to tear down and reassemble the machine, and, of course, the location of any internal batteries.
I don't remember for certain (without the manual) on the 600 series, but some Thinkpads have THREE batteries.
1--the main battery
2--the bios battery--the one you want
3--a third battery which "holds" the settings during standby/sleep time
I'll see if I can post the URLs