Siemens EQ5 TE515209RW03, "no beans" displayed although there are beans

Hello, I have a Siemens EQ5 TE515209RW/03 which has started to display that the beans should be refilled even if there are beans present. Sometimes the grinder runs for about half a second (and sounds strained), but normally it does not move at all before the message is shown. I have tried to disassemble the machine, but although I have managed to release the catches that hold the bean container, it will not get completely loose. I suspect that I have to remove the grinding coarseness setting knob first, but I do not know how. In the EQ6 service manual it says that the knob should be turned all the way CCW and then pulled out (and I suspect it is the same case here), but I cannot turn the knob all the way CCW when the grinder does not move. Do you have any suggestions? Best regards Jonas
AI: Have you tried cleaning the grinder and the bean chute to ensure there are no blockages or old coffee residues that might be causing the “no beans” error? If so, did you notice any improvement or changes in the grinder’s behavior?
Yes, as far as I have been able to reach.
AI: Apart from the “no beans” message, does the machine display any other error codes, warning lights, or unusual behavior (such as strange noises, leaks, or other malfunctions)?
No, only as described above

The knob should be set to the lowest grinding setting and lifted with a screwdriver.

Thanks, the problem is that there are coffee residues in the grinder that prevent the knob to be turned all the way to the lowest grinding setting, and since the grinder is not moving, the residues do not go away. Is there any other way to move the knob, or any way to force the grinder to turn?

If you challenge it, it will also go away.

Thanks, I will try and see what happens.

Hello, I managed to disassemble the machine today, removed the upper ceramic grinding stone and cleaned the grinder. When assembled, the error is still present; the grinder does not move when a coffee beverage is chosen, and the “no beans” message is displayed. What triggers the “no beans” message, is it an optical sensor (I saw none) or a grinder motor current measurement? But should the grinder not move before the current may be measured in that case? How do you propose that I continue, what can cause this error – broken grinder motor?

No power to the grinder. Brushes in the grinder damaged, thermal fuse in the grinder damaged, grinder itself damaged or electronics.

OK, I will check - thanks!

Added after 4 [minutes]:

I have two more questions; is there any way to do a complete reset of the machine (if it is in a locked state), and how often are the brushes to be changed (we have had over 8 000 cups of coffee made). Best regards Jonas

Hello, I have now removed the motor and can see that one brush is gone, only one is present. I will buy two new brushes and test, Thanks!

Two new brushes installed, the motor runs again and we can get nice coffee - thanks!

It should be noted that someone helped.