Well crap. Now that I know I had the pins backward, I know why the fuse on the primary side of the transformer was blown. The secondary winding powering the tube heaters is shorted out. And the fact that someone jumpered around the fuse means they probably tried to turn it on again without fixing the underlying issue and may have fried more stuff. On the plus side, this thing doesn't have any ICs to kill; it may well all be stuff I can replace.
Assuming I can find a new transformer....
I'm going to give it a good try, but this may end up being a parts machine if I can't. I'll confirm the issue at home by desoldering the secondary outputs and checking continuity across them.
Assuming I can find a new transformer....
I'm going to give it a good try, but this may end up being a parts machine if I can't. I'll confirm the issue at home by desoldering the secondary outputs and checking continuity across them.