I read somewhere about those units developing shorts. I would take the ignition assembly apart and look for anything affected by heat, like something melted, blackened. You could always turn the unit on and try to seee what is heating up real quick. I'd check out EBAY to see if you cab get a reolacement cheap. if that ends up being the problem. If you had the schematics, you shoulod be able to jump the wires and get everything working by passing the ignition assembly. A PITA but troubleshooting always is.