I just plugged in my old ARP Omni, and it still works. Although the volume is increasing staticky. When I move it, the static increases in volume. I figure there is so much dust in there, that is what is causing the problem, or at least part of it. Two keys are dead, due too snapped contact wires under the keys. The string section, still plays alright, but the synth section is a bit sketchy. The 8' still works, but not the 4'. The Chorus Phaser and Waveform Enhancer don't work. The LED light are dead, and I think the buttons are too. Only the 8' Synth Bass works, but not the 16'. the sliders on the left side of the keyboard seem okay, but the ones across the front panel and very sticky. I had this synth repaired, back in the 1990's around the same time I bought it, but I don't think the people who repaired it are still in business. Even though it has it's problems, I hate too get rid of it, since I have had it for so long.