Sounds like the memory block is completely damaged.
Look for traces of damage to the circuit board.
It may require some kludge work if the traces have become damaged from
a leaky battery.
If this is the case and the techs where you are cannot perform this
type of work I would start looking for one who can.
I have an excellent tech here where I live in Wichita KS.
Mike Metz his info can be obtained from my site.
-Visit Dana's Synth Site
http://members.cox.net/synths