I found it interesting that the main transformer is potted in a block of silicone way off to the side.
So I get to work taking out all the screws and popping all the power devices loose. Hello, what do we have here? Seems one of the devices got the ass blown out of it. Fairchild HGT40N60A4 600v IGBT, neat. Looks like I can still buy one from mouser for $13. I hope the gate driver IC hasn't died with it. Maybe I should order one of those just in case.
The traces between collector and emitter are gone. Main fuse still A-OK though. Makes sense though, there's a crapload of capacitance on the main rail. Probably made a good bang when it went.