In order to get it to operate a barb on the rim of the grinding chamber cover manipulates a tab on the rim of the grinding chamber when the cover is screwed on to the chamber. The tab is attached to a safety switch which energizes the ON/OFF button. The plastic barb and the plastic tab start to wear out after being use about a dozen times and will eventually no longer manipulate the switch and the grinder will no longer function. This will leave you to take the grinder apart by opening the bottom, unscrewing the blade, removing the rotor from the housing, yanking the wires going to stupid safety switch and solder a bypass using one of the lines and then put the whole damn thing back together again in order to grind your coffee so that you can have your first cup in the morning so that you can wake-up to curse the idiot engineer who designed it.