I would like some thoughts. I recently purchased this older "Miller 250 AC/DC HF tig metallic Arc welder". I believe it is prior to the Dialarc series of Miller's. Big brute of a welder that deserves a good home. It has a 2 pin 20amp Hubbell connector in the top left of the face plate that should be for a contactor. The Dialarc 250 AC/DC HF has a similar plug but also has a 3 pin that would be for the variable amperage control. Does anyone know how similar these two welders are and if I can wire a 3 pin amperage control into the model I own?

Thanks for your thoughts