Hi Jerry. Thanks for the response. It's the 6A fuse that's blowing. I've had these amps for 20 years and they haven't even been moved in four years. They've had the same fuses the whole time and it just started doing this about a week ago.
The fuses were definitely in the right places. First thing I did swap the tubes. I opened it up to see if I could find any obvious shorts or anything like that. There were some spider webs, which I know can cause shorts, but I cleaned them out and tried it again to no avail. All I can say is it's nothing that would be obvious to a layman.
I'm in KY, so either coast is going to be a long haul to ship. I just emailed the authorized service center in NY to see if they know if there's something that commonly happens that I might be able to do something about. Fingers crossed.
I bought these and the InControl preamp used for less than half of retail, so I suppose I should be happy I've had them this long. But they've been a PITA since I got them. The preamp quit on me almost immediately, so I had to send it to NY and wait several months to get it back because the parts had to come from Italy. Then a few years ago one of the amp capacitors leaked and I had to get all of them replaced. In that instance I was at least lucky enough to have someone local to do it. Unfortunately, I've moved since then and I don't have anyone here to fix it. If I do end up having to replace my gear, I don't think I'll trust Pathos again.
Best - Brian