Check for 120vac on the leftmost connector of the inverter board. You should have 120vac between wht/red and red/blk as well as between wht/red and orn. If ok, and you don't see the flashing green LED, the inverter is bad. If the motor has been replaced within the last couple years, the new style motor has a flap on the right side. You must lift the flap to see the LED which is now red, vice green. The inverter is not repairable/replaceable, you must replace the whole motor/inverter unit. New motors come with a jumper to replace the fuse which must be removed. Make sure you get the right motor/inverter, there are about 5 different versions and they are not interchangeable.