Took a new job teaching at the local vocational school. We have 3 300 Miller dx machines.One we have set up for aluminum tig will arc when you use the foot petal but will just quit a few seconds after it starts.No code on display.No manuals for any of them,I can get them from millers website. It is a good machine and I'm sure it will weld great if it gets figured out. I like my old faithful Syncrowave 250. Appreciate any tips you may have. Thanks