I have a Karcher K620 MH high pressure washer which won't start. The green pilot light on the on / off switch is illuminated when connected to the mains, so I assume there is power to the unit. I have carefully stripped it down and other than the motor being knackered, I can only assume it is the capacitor or on / off switch. I am not an electrican, but have a multimeter. Does anyone know what I should set the dial to to test the circuit on the capacitor please. Also, does anyone know how to test the switch circuit please. I would also appreciate any other clues as to what the problem may be. Thanks very much.