I wonder if this may be down to the door interlock switch. There seem to be various types, but modern machines link the interlock to all the other functions of the machine - if the interlock doesn't work power fails to the rest of the machine.
If you decide to try changing the interlock you must ge the right one - you'll need to know the machine model and serial numbers (preferably even the number on the existing interlock)
Might be wrong though...
J, January 2005