Okay, so the amp was blowing a fuse (the small one on the board)every time you turn it on. I replaced all the tubes, assuming one was bad... But they all needed replaced anyway. That fixed the fuse blowing instantly. Now I can turn the amp on, play it for a while, and when I shut it off, it will blow the fuse if I turn it back on. Is this most likely a bad filter cap? They all look okay, but I guess that doesn't mean anything. If replacing those doesn't fix it, would that mean it is probably the output transformer?