The high failure item I have found on that model. Is the A1 board. It is a two piece control system. Has a DC and an AC side. No AC output will cause a shutdown. I would say 90% of the problems I found was the board. If you go to check the brushes be careful when pulling the flywheel. The key stock to lock the wheel to the shaft. Is about the size of a BB very easy to lose. You should have manual 981-0530 to go by. It has all the test you need to check it out. You don't need the remote hooked up to run it.