MMU2S drum not selecting correct filament  

John Wohlers
New Member

Yesterday in the middle of a print we received an MMU needs attention error.  I looked over the MMU2S and could see that the filament was not loading.    Upon closer inspection we noticed that while the LED and the filament selector were set to the appropriate position (Filament 3) the idler drum was actually sitting rotated halfway between the position for Filament 2 and Filament 3, thus not putting any tension on the filament.   We tried to reboot the MMU2S in hopes that it would re-calibrate itself.  It did not. We ended up canceling the print.

We can no longer use the printer as the MMU2S seems to be consistently confused about the drum position.   Manually selecting a filament position using the buttons on the MMU results in the selector moving to the correct position, and the drum also moving to the correct position.  However if you try to load the filament from the LCD the drum rotates half a position once again, and no longer comes in contact with any filament.      Video: 

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We checked the Idler Drum screws, and everything seems to be tight. Filament moves freely through the PTFE tubes manually.  

We have tried a factory reset on the MMU2S, and that didn't seem to make any difference.   Does anyone  have any ideas as to what we can do to get the printer working again?

MMU2S Firmware Version:  1.0.6
MK3S Firmware Version:




This topic was modified 1 year ago by John Wohlers
Posted : 03/11/2019 8:07 pm
Active Member

Same thing happened to me, the problem was that the drum was not positioned in the right angle with the motor shaft. tightening the screws I actually broke the drum and I had to reprint it..... try to disassemble the drum and reassemble it.... That worked for me.... I hope it works for you.

Posted : 04/11/2019 7:05 pm
Noble Member

I would suggest to contact Live Support. They will guide you through the steps and provide replacement parts if needed.


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Posted : 04/11/2019 9:50 pm
Active Member


how do you contact live support?

Posted : 04/11/2019 10:02 pm
Dave Avery
Honorable Member

log on to the e-shop with the email you used to buy the printer and the chat will pop up in the lower right corner of the screen ( disable pop blocker)


Posted : 05/11/2019 4:34 pm
Active Member


got it! thank you

Posted : 05/11/2019 5:31 pm

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