As soon as I turn the dishwasher on, the solenoid valve controlling the powder dispenser activates (emptying the powder into the machine) and then stays activated - I can hear it humming.
On my machine (AEG Favorit), I unscrewed the front door panel and squirted some WD40 into the electromagnet that controls the dispenser door (you'll see the spring activator).
Let it dry, then retry
