Prusa i3 MK3S MMU2S Bear Extruder-Idler-Lucky Mod

thingiverse

I'm definitely standing on the shoulders of giants with this one. I have the Prusa i3 Mk3s with the MMU2S, but unfortunately, I've been unable to print anything reliably yet. The main issue seems to be the IR sensor, which has been problematic from the start. To troubleshoot this, I swapped out my stock extruder for the Bear extruder, which is much easier to disassemble. However, I encountered another problem with the MMU2S - the door sensor wasn't triggering the IR sensor reliably, despite trying Vertigo235's solution. Despite many close calls, I couldn't get it to work. Before switching to the Bear extruder, I experienced similar issues with the stock idler door and the chimney, where the IR sensor never triggered properly. To address this, I used a mod that modified the idler door to include a small M2x10mm cap screw through the lever that triggers the IR sensor, allowing for fine-tuning by adjusting the screw's position. I decided to combine elements of these mods and create a new version with the chimney and the fine-tuning mechanism. The main drawback compared to Vertigo's design is that the idler door can't swing all the way up. However, even his version required removing the sensor arm to allow the door to open fully, which was a minor hassle. With my mashup design, you'll need to remove the entire idler door, but this isn't a significant issue for me. I've printed and assembled the parts, and I'm currently running a test print - so far, everything seems to be working as expected. I'll post further updates here as they become available. P.S. - To complete my mod, you'll also need the chimney sensor cap that comes with the MMU2.