Sequential circuits samplers

hi everyone! I just joined this group as I just won a prophet 2000 on ebay. The built in preset sounds don't all work though. I think 4 of them work. These were just basic waveforms stored on the internal rom, right? So, I don't know anything about the internal stuff in there, but could the ROM be damaged or gone bad in some way that only some of the waveforms are lost but others are ok?

I've looked through the back history in here and a couple other people had this issue but never mentioned if they resolved it or anything. Anyone know how this could be fixed or what might cause it?

I've tested the 8 voices and they all work fine.