2400c not charging/seeing battery

[Steven Patterson]

I have a 2400c/240. It's showing some weird behavior:
Wouldn't sleep at first, but worked OK off both battery and ac.
Now works fine off ac, but doesn't show battery in control strip.
If I remove battery and replace it the control strip shows battery for 
a few seconds then it disappears again.
Used known good batteries.
Tried zapping PRAM, resetting power manager, but no luck, any ideas?
If I can't get it working I'll take 240 MHz card and put it in the 
2400c/180 which is working fine.
If this is a motherboard problem will the cpu card still be useable, 
and can I keep the cardbus enabled slots or is it all on the same board?
Thanks
Steve