This Korg Poly-800 Mk1 had suddenly started to behave oddly. If it made any sounds at all they were inconsistent and random. This would indicate that the memory is corrupt due to a bad battery. As I understand it there was no internal battery mounted in all of the Kort Poly-800 Mk1, they required batteries to me munted in the battery compartment on the bottom. In this machine the internal battery does not look original and one trace has been cut so I seems to have been modded at some point.
After the battery has been replaced the RAM memory has to be restored from a factory preset tape load file. This can be found in many placed; but here is one source: