One of these things is not like the others...

[gui_tarzan]

Actually it has three different output tubes. One is definitely not well, can you see the issue in the pic with the single tube?

[g1]

Getter creep?
I have a lovely new NOS GE 6550 with a broken getter holder rattling around in it. Works fine in any amp that hangs the tubes upside down.

[gui_tarzan]

Three of the tube bases are loose and several of the pins have bad or iffy solder connections. The poor guy just bought this and said it worked fine at the previous owner's house, but when he got it home it started popping and making all sorts of noise.

[The Dude]

Not that you don't already know this, but unfortunately, that's to be somewhat expected with used tube amps. Tubes wear out. Caps dry out. When you buy a used car, you expect (or at least you should expect) that you will have to do some maintenance and that many of the parts are past their prime. Older tube amps are no different in that regard.

[gui_tarzan]

Oh I know, I just thought it was odd and it was a conversation piece.