Metropoulos Forum

Hi!
I just bought a 2nd hand metroamp factory built jtm45. The amp looks brand new and the workmanship on the inside is beautiful.
I had a built a couple jtm-45's years ago and mine never looked nearly as good lol.
The gentleman I bought it from said he had it in storage since he bought it 2.5 years ago and it looks like it.
Well, I played it on 10 for about 30 minutes yesterday and 30 minutes today and it sounded great but I just started to have problems with it all of a sudden. I had it on standby for a few minutes while I was playing my other amp today and when I turned it back on it had a loud hum.I tapped the top of the amp and it went away for a couple seconds but came back after I played it again.
Then, it lost a good bit of volume and finally lost even more volume and developed a non-musical grating type of distortion.
I'd say this was all during a period of 2 minutes or so.
Have I fried the transformer? The tubes glowed or slightly arced a slight blue when I was playing it but other than that they look fine. Also, I checked both fuses and they're fine and I looked at all the connections and didn't see any burn marks, etc.
Any ideas? I've attached some pics.Thanks so much!!

First thing is remove the tubes and replace with known good ones, make sure they are seated well in the sockets.

The responding to a thump temporarily might be a clue!

Thanks man! I'll try some more tubes first

Thanks y'all!
I bought some gold lion kt66's and Rebiased and all is well