I have the MK3S with MMU2S. I bought the MK3S+ upgrade kit. What now?

I have the MK3S with MMU2S. I bought the MK3S+ upgrade kit. What now?  

Active Member

I have the MK3S with MMU2S. Both are already assembled (MK3S bought in Q1/2019; MMU2S added soon after). Both are fine and everything is working well (including the MMU2S).

I bought the "Original Prusa i3 MK3/S to MK3S+ upgrade kit". I specifically want to have the SuperPINDA, and as far as I can tell that means I have to do the extruder upgrade.

I found no instructions on how to do that. The MK3S -> MK3S+ manual https://help.prusa3d.com/en/guide/1-introduction_186036 specifically says that it is only for the single-filament version, not the MMU version of the extruder. I asked Prusa support and they told me to only print the 4 extruder parts from https://www.prusa3d.com/prusa-i3-printable-parts/ (which I did) and then follow steps 2b and 3b of https://help.prusa3d.com/en/tag/mmu2/ . This is the "Original Prusa i3 to MMU2S upgrade", i.e., the original upgrade manual for the MMU2S (which I did long ago) - if I open that link on PC. On my smartphone, which I am using when I am working on the printer, that link instead lead me to the single filament version https://help.prusa3d.com/en/guide/1-introduction_186036, which I noticed belatedly (and I assumed that it is the correct one, as it was linked by support, anyways 🙁 ).

Now I'm super confused where to go from here. I thought nothing about it at first and already disassembled the cable bundle and extruder as per step 2b of that manual. Now, reading a bit ahead in 3b, I have the strong impression that only printing those 4 extruder parts they instructed me to print was not enough; it is all very fuzzy and unclear. Both manuals I have through that one link (the MMU2S upgrade manual, and the MK3S->MK3S+) seem to be wildly irrelevant to what I am trying to achieve, since they show plenty of imagery which is pre-MMU2S-upgrade, and at no point there is a clear indication of which "+" extruder parts go with the MMU2S extruder.

Before I go any further, and since I fear that I have to roll back what I did so far to be able to maybe print more pieces, I'd like to ask:

What *exactly* do I need to do to upgrade a finished MK3S/MMU2S combo to use the "+" version goodies? Which parts *exactly* do I need to print? Do you have correct links (deep links to the actual parts and manuals, not, as I understand now, generic "category" links the Prusa support mailed me)?

Or is that combination (MK3S/MMU2S *already built*) not yet supported for the "+" version?

Thanks in advance and sorry for the long post with many repetitions. I do realize that there are a great many of combinations and versions of printers and MMU2S'ses, I'm just trying to be as specific and clear as possible... 😉

This topic was modified 4 months ago 6 times by OutOfMuc
Posted : 13/02/2021 4:47 pm
Active Member

The parts I printed were those, if it matters:


Posted : 13/02/2021 4:54 pm
Active Member

Ok, well, I downloaded all the .stl's that were changed for the MK3S+ upgrade from github, and the previous versions and compared them visually. The extruder body and others *did* in fact change significantly, and it is clear now that the advice to only print those 4 parts made no sense whatsoever. Also, the changes do seem very useful to me, should help against TPU jams a lot. 

I'll reassemble everything, print those missing parts, start over, and just go by trial and error to cobble everything together. Not quite the usual Prusa experience, but can't be changed now. Guess I learned something for the future at least; make better use of the open source feature and find out how stuff fits together myself instead of relying on documentation or support, at least as far as the MMU2S is concerned. 


Posted : 13/02/2021 9:01 pm
Active Member


Just curious if you have an update - were you able to get it all sorted?  I too have an MK3S + MMU2S and wondering about upgrading to the MK3S+ but am confused as to what I actually need to proceed.

Posted : 12/03/2021 4:15 pm
New Member


Any updates?

Posted : 12/05/2021 9:43 pm
Prominent Member

As far as I understood it the MMU2S, when I bought it in Dec, said it required the MK3S to be updated to the MK3S+ first.  When I received the MMU2S kit and the MK3S -> MK3S+ upgrade kit, I did the upgrade to MK3S+ first which required replacing the pinda with super pinda and printing new extruder body parts.   So that MK3S+ upgrade from MK3S should be all you need to do.  That was pretty involved.

Posted : 15/05/2021 5:50 pm

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