Thermomix Tm21 Manual Link
The TM21 manual includes an exploded parts diagram. The blade assembly is replaceable by a service center only. If you hear a grinding noise, the manual states: “Stop use immediately. The bearings are failing and may release steel particles into food.”
According to this rogue appendix, if you held down the “Turbo” and “Reverse” buttons for 8 seconds, the TM21 would enter a secret mode. It wasn’t for chopping onions. It was for listening . thermomix tm21 manual
Based on forum searches and customer service logs, these are the five pages TM21 owners look for the most: The TM21 manual includes an exploded parts diagram