In a repair shop, its hard to justify 2 hours labor plus $20 on parts to rebuild a board ($140), you can't offer warranty on. I'd rather send it to Innovat Corp, get it completely rebuilt for $250 and offer a one year warranty.
Id this the same machine you are trying to get a new torch for? Here is what the torch should look like:
http://www.millerwelds.com/om/o2210n_mil.pdf