Probably the inverter, the power supply is always the weak spot. I would make sure that they have a return policy wherever you get it though in case I'm, uhh, wrong.

It would probably be a 10-20% fee but it beats eating the whole cost at that price.

I would pull it apart and see what the board looks like first. I don't think I have any manuals for the aluminum models, I'll see what I can find unless you come up with one first.