I agree that sending the unit to Krell is probably the way to go. I noticed an ad for Krell MDA 500s that mentioned servicing by a company in Bridgeport, CT called The Service Department, a possible alternative, though I don't have any experience with them. Do check to make sure you haven't just blown a fuse, though.
While Unsound is probably right based on his longer experience with the 3.5s, I'll note that I did use a Krell KSA 50 Mk II for my Thiel CS3s for a while (till I sold them to get Duntechs) and in my moderate sized room (20 by 18 feet) it drove the Thiels with no strain. It's a lot more powerful than its power rating would imply.
By the way, I (and I think most of people who posted) am assuming that you are talking about the original KSA 50, and not the later KSA 50s. Is that assumprion correct?
While Unsound is probably right based on his longer experience with the 3.5s, I'll note that I did use a Krell KSA 50 Mk II for my Thiel CS3s for a while (till I sold them to get Duntechs) and in my moderate sized room (20 by 18 feet) it drove the Thiels with no strain. It's a lot more powerful than its power rating would imply.
By the way, I (and I think most of people who posted) am assuming that you are talking about the original KSA 50, and not the later KSA 50s. Is that assumprion correct?