When the dishwasher starts, it runs the drain pump as usual and then just hangs when it should be filling with water but isn't. It has an aquastop type fill valve and I have taken the cover off that and it is not getting any power from the machine to open the valve. I have replaced the pressure switch but it has not made any difference I have tested the door switch and it's fine. What's the most likely cause? Capacitor? Circuit board? Something else? Thanks in advance