I got my Series electronics from someone on ebay. It was basically the board and a pile of parts, most of which I replaced. While it's not a crazy difficult circuit, I would not suggest it for a beginner. I also believe that tuning the whole thing to work just exactly right is not trivial. While the SII setup I rebuilt does function, it's somewhat noisy. My SI is dead quiet and Ron worked for a long time to make it so. I don't know what he did, but whatever it is, he's very good at it and it adds a lot of value to factory setups.
