The Kawai & Teisco Analog Synths Group

Hi,
I have an sx210 that has been doing fine for a few years now.  I have
read all the warnings about having the battery changed, but have not
taken care of that yet.  It's been in my studio, unmoved and operating
fine, until I took it to my rehearsal space a few weeks ago.  When I
powered it up there, all patches but one in the first bank were
unnamed, and seemed to have reverted to default values for all
parameters.  The other banks have been fine.  I opened up the keyboard
last night to check the battery, and there are no signs of corrosion.
 I plan on changing the battery anyway, but I am not confident that
this is the problem.  The keyboard was jostled a bit during transport
to the rehearsal space.  Does anyone have any recommendations for
troubleshooting this problem other than battery replacement?  Also, I
remember reading about what kind of battery (and resistor?) to replace
the ni-cad with somewhere, but I can't seem to find it again.  Anyone
have any tips there?  Thanks very much for any help.
Brian