Bill, right, the 170 is 220 volts; both are built on the same platform.
You say that the power supply gets hot and the welding power drops off. I am surprised that the overheat sensor did not trip. Maybe what is getting hot is not in contact with the overheat sensor. Someone mentioned that some transformers are wound with aluminum wire, that could be a problem in it self.
I take it that the fan is in good working order and that the air vents are all wide open, and air is not leaking from gaps in the cover?]
Transit,I took my welder apart over the weekend and disconected and reconected every connection I could find. I did find a slightly loose conection on a ground lug. I put it back together and it welds perfect! I don'tknow what I did to fix it but I glad it did . It saved me about $1000. Thanks for giving me the idea.