Its been over 5 years since I visited Wil at his shop. There did seem to be some other folks around at the time, but not sure what their roles were. I just used the number from his website. He was usually pretty good at answering the phone, but sometimes it did take a few attempts. Sorry I cant help more.
My AP4 is still going strong, although its just my backup AP these days and I seldom turn it on. Were I in your part of the world I might be persuaded to sell it, but not very practical to do that from Australia. The units were very popular in the PNW, so perhaps you could contact some of the yards there in case they can give you some leads.