MD-Pro (Tototek) Save feature fix?

Hey folks,
So I created a thread about this over here:
http://www.sega-16.com/forum/showthread.php?30053-Totoek-MD-PRO-(Save-feature)&p=720175#post720175
but I think people here are much more knowledgeable about this kinda thing. I have a 64M Tototek MD-Pro that is having save issues. It flashes fine and plays everything else but when I save a game it will retain the save for a short time (or sometimes it won't at all) before the game save evaporates from the memory. The battery has been changed a couple times to try and fix this and the one in there now reads 3.1v which I think should be enough. I changed the capacitor inside and reflowed the chips which did nothing ( heh, worth a shot!)
any ideas would be appreciated..