I did some searching but couldn’t find a schematic. A couple of old forum posts mentioned the company might be helpful, but this thing does seem pretty old 8) I’ll try calling them tomorrow, in the meantime I’m sketching one on the back of an envelope. I could not find any model number or ID plate, just the company logo on the little keyboard. Any restoration tips greatly appreciated, as always! I’m thinking about doing something crazy like a Bluetooth and/or MIDI interface for it.