It looks to me like a bad capacitor crapped-out and caused a short.
This was a v1.0 Xbox...

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How long ago did you phone them? Doubt they'd give an original Xbox now as a replacementprofessor_jonny wrote: ↑Thu Sep 07, 2017 1:27 am I have had that happen.
I phoned Microsoft as it caught fire and they supplied me with a new XB1 for my troubles
they classed it as prity serious and wanted serial numbers pictures etc...
mine was a lot worse than that it warped the dvd tray and case, it self extinguished it's self but it bellowed heaps of smoke tho.