I can't help with history. With repair: Give the thing a good clean inside. Don't use oil on anything. Photograph it from many angles in good light, as it is when hoovered out, with the panels and keyboard covers off. Take the action out, photograph more, and the action, and areas with problems. Stick all the pics in a Picassaweb or similar album and post a link. Lots of pictures please.
Pleased to hear that you have found this. Sounds much more fun than anything electric!