I don't have a diagram for that machine handy at the minute (Ill see if i can dig one up and then post back), but if I understand you right the feed motor is not running at all. I'm not insulting your intelligence here, but if the machine has tapped voltage settings, make sure the switch is not stuck between positions. If that is ok, check out the switch itself to make sure no contacts are burned or loose. And off the top of my head if the above checks out its probably the board
Lincoln will probably not cover the machine if it is out of warranty. We get some of the industrial machines in with the transformer coils loose (which is a manufacturing defect) and they won't cover those.
Good luck and I'll see what I can find on the machine.