Another issue I have started to notice on about 3/100 of the GX-270's is the south bridge fries. If the south bridge is bad it will be super hot to the touch and you will most likely notice dark black spots or if it was really hot a white powder. If that chip is fried its probably time for a new board. Location of the South Bridge.

This is most likely caused by Latchup which shorts the power rails through the silicon die, burning it up.