I had a Hot Rod brought to me last week, no power tubes, the fellow had been using the preamp out into a SS power amp, back into the combo speaker. I installed a couple of tubes, plugged in the speaker, and fired it up, nothing, power tube heaters not glowing. Moving the tubes got one to glow, so I looked closely at the solder connections on the tube board. (I had heard they have been problematic).Touched up all connections, (with "real" solder), and tried it again, sounds pretty good. I didn't find noisy jacks, or burned traces like I've seen on the Jr's, so I guess the guy lucked out. Ordered new JJ's for it, (almost $50 cost!)
TJ used to gut these things, and build classic amps from the pieces, but I think this one has a little more life in it!