Welding machine help needed Hobart

I had one of my old mig welders on the bench, was welding a bracket,and it touched the welder and i didnt notice, it blew out the control board. It behaved very similar to what you describe. So if welder housing was touching car body as you were welding, this may be your issue. Hope it is something simple, but if your luck is like mine,it wont be.