Welder gave out on me.
you can try calling these guys on monday
http://billswelderrepair.com/parts-page.html
there are some welder schematics on that page, not your brand that i can find but it is interesting to look at
they might be able to point you in the right direction, as to what commonly fails, what matches your symptoms, what parts you might need, where to get parts etc.
good luck bro