This modifications of the original prusa MMU2S extruder, were the only way i could make it work properly (for me). It has been really frustrating months, there is a lot of ideas you can find searching in forums, i tried all of them and some of them work but nothing that make it work all the time. I was about to give up, but then I realiced that if there is a lot of diferents modifications it was because "you have to solve your own problems". For me, it was this.
Features:
Pass thru ptfe tube (3mm ID 4mm OD) Almost all the way to the gear.
Side window (for cleaning, watch and understand the filament feed)
It feeds almost all kind of tips.
What you need:
PTFE tube 3mm ID 4mm OD
4mm Pass thru couple
https://www.amazon.com/gp/product/B01IB81IHG/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1
Assembly:
Printed in PETG (No support)
The same that prusa´s manuals.
Make sure the PTFE tube rest in the proper place.
Layer: 0.15mm
No support
The author hasn't provided the model origin yet.