I have a PowerUltra205 that is unable to power on.
This it the 2010 model I think.
A friend was Tig welding with it one day and forgot to put on the ground clamp on the stainless piece I was working on.
Told me when he touched the electrode to the piece he heard a pop from the box and the unit powered off and I haven't been able to get it to power on again.
I pulled the cover and on the right bottom rear I found a wire from the secondary side of the transformer just disconnected.
This is the transformer closet to the rear of the box.
I could solder it back to the board but I'm not sure where it is supposed to go.