Ive got a reissue Fender Super Reverb and it started making this nasty whining noise and the signal completely cuts out. the volume has no control over the sound and the sound will happen without anything plugged into the amp. I've tried to switch out the power tubes and I still get the sound. Has anyone had this problem or have any thoughts on this? I was able to make the sound go away for almost 2 weeks by pulling the tubes and putting deoxit on the connections. But tonight it came back and I couldn't get rid of it. Thanks.