Got my Mesa back from my guitarist because it's been acting up, with volume randomly increasing and decreasing.
First things to check are the power tubes, so I swapped in my old reliable testing set, turned it on, and started playing. Then stopped when I started to smell an unmistakable "hot electronics" stench.
Guess my "old reliable testing set" isn't quite so "old reliable" anymore:
I don't think i've ever seen an EL84 redplate like that!
My Budda has started to do weird things too, so it's up next on the bench after I sort out the Mesa.
I did that to my Nomad right after I first got it