My Miele W844 will not open when the “Open” button is pressed. I hear a sound as if a relay is trying to operate at the mainboard and if I hold the button it will click repeatedly about twice a second. It will open manually. The machine is 20 years old but in exceptional condition. I have changed brushes,dampers etc and am quite useful with a soldering iron so would appreciate any suggestions before I resort to calling an engineer. This is my first post so I hope I’ve got it right.