MDX On-Demand Grinder

Hi Everyone,

We have a 5 year-old Nuovo Simonelli MDX On-Demand Grinder.
Lately it has been grinding a 2nd dose immediately after the first, before we can even remove the portafilter. We’ve cleaned it in side and out, adjusted the height of the portafilter rack, and cleaned the sensor but no luck. Has anyone else seen this behaviour?
Battery Cafe, St. John’s Newfoundland, Canada