Okay, same problem, but I was able to capture the intermittent nature this time.
One thing I forgot to mention is that tapping near the tuner seems to impact it. I didn't capture that part effectively, but it went from normal static visual and audio to everything cutting in and out maybe ever 20 seconds. Then I tapped the cabinet near the tuner and it started cutting in and out much faster. Loose connection somewhere, maybe?
Anyway, here's the video:
https://www.youtube.com/watch?v=yXLR...ature=youtu.be
I may see about pulling the back off and reseating the tubes at least. Not sure if that'll do much or not, but I suppose it can't hurt.