Hale970, Not sure of your problem.These units are very power sensitive I would start by checking battery voltage or try a new battery. Check battery conections. If you can check pin voltage, where it plugs into back of unit. Is it hooked up to the cranking battery? Can you check it on a friends boat that you know works O.K. The fact that it worked originally makes me think it is a voltage problem. It only needs a small voltage drop to not power up. Good Luck, hope you solve the problem. Sorry I could not be of more help..... crappie1133