MMU2S with Mk3S idler homing not working after firmware update. A solution!

[hjvooijen]

As discussed in Github #4285 the MMU2S suffered idler homing problems.
The SW people were looking for solutions while changing sensitivity values.
I found that the motorshaft and Idlerdrum cannot be perfectly aligned. Also that the motor mount was not perfectly square to the Idler housing centerline.
My route as a mechanical engineer was to eliminate the over-determination .
Based on tolerances on the Idlerdrum connection to the motorshaft and the mounting plenum of the motor self, I changed the motor mount into one providing 2 extra rotation freedoms.
My machine is now working fine without any changes in sensitivity values with the latest firmware.
Read my doc please and try my .stl's on printables under MMU2S+ 🤭
I reach out to Prusa engineers to understand what I did and why.
For discussion available,
Henk van Ooijen

MMU2S solution for firmware updates.pdf