On some of these the board gets it's power from the pump. It has a normal 110v plug in the side of the pump that goes to the board. If the pump shuts down, so does the board. A) determine if this unit has a large pump in the back beside compressor. If so B) remove pump and clean out impeller area C) reassemble and test. IF that doesn't fix it, you likely have a bad pump motor. Very expensive.