I have an old yamaha dx 100. I think I bought it in 1986. Yikes!
Anyway, I haven't used it in years, but it isn't damaged and was always in working order. It doesn't work now, but is it possible to get it working again? Maybe an internal battery needs replacing or something? I don't know.
I had a great time programming that thing back in the day. I was thinking maybe I could sample some of the sounds into the my Motif. Or show it to my students.