XMT 304 blew up.

[Portable Welder]

My XMT 304 is approximately a 2002 or so with a Ser# LA 195408 the stock # 903471 230/460
Anyway, we were using it out on a job, I had it wired to run 480 single phase, we had been using it, one of my guys left it running during lunch, after lunch we went back down inside of the tank we were working on, I unplugged it not realizing he didn't have it shut off and when I plugged it back in I heard a not so nice thud when I plugged it back in and some not so good smells....
So, is she smoked or not ? is it repairable for a reasonable cost and if I do get it repaired is she on her last leg ? I do realize no one knows until it tore apart and inspected, but a loud thud and smoke tells me shes done.

[Bushytails]

If it turned off, made bad noises, and emitted smoke, then I would wager that, yes, it's broken.

The XMT304 is quite repairable, unlike the newer XMT350 and such. First thing to do, if you want to repair it yourself or just get an idea of what it'll need, is pop the cover and look for anywhere the magic smoke has obviously escaped, then download the service manual (you can find it googling) and follow the pre-power inspection checklist, which will usually (but not always!) give you a list of what failed. The newer machines use integrated modules where any failure requires replacing a module that costs more than a working welder goes for, while the XMT304 uses easily available and replaceable parts.