These machines were designed to disengage the gearbox when the cover (where the blender goes) is removed, the theory being less gear train resistance more power to spinning knives/blade. Is this the cover that you are referring to?
Question moved from Cars and Trucks.
Stand Mixers don't normally have belts and I don't believe this one does as I can't find spare belts. They are operated by nylon cogs that run in grease. The most likely reason is the she shear pin has sheared. This is a small pin like a nail that goes through a cog or shaft and shears if too much load is put on the mixer beater or dough hook. It often happens if you make bread and have the speed too high.
https://www.google.com/search?q=change+the+belt+in+a+Bodum+electric+mixer
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You will need to get a qualified electronics technician to look at it. The issue could be anywhere on the circuit boards inside the mixer. Unless you know what you are doing don't try to repair it yourself as you could make the problem worse.
Spray some WD40 into the eject button. The wait 10 minutes and turn it upside down and spray WD40 down the side of the beaters Leave 10 minutes and try again/ If that doesn't work, you will need full disassembly
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Push the head down before pressing the button on the mystery mixer. There is probably dough under the hook with it pressing the head up and is locking the catch.
You can pull out the dough around the dough hook to make it easier.
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