MK3S new from factory filament sensor stuck on  

MK3S new from factory filament sensor stuck on

Apologies if this is the wrong forum...

This is my first Prusa, and first printer, although I have printed hundreds of things through bureaus before. I was in the backorder queue for a while and was lucky enough to get one of the first MK3S's off the line a week and a half ago (fw 3.5.3). Overall I have been super impressed. Everything I have thrown at it has worked basically out of the box with no tweaks. However, I did have a slightly sub-optimal startup experience, and had to tweak the new filament sensor to get it working.

When I first unboxed the unit and took the test print off, I figured I would print out the test Prusa brick the first time. I selected unload filament, pulled the stub from the factory out. Then I just went to print from SD card to print the prusa logo. I figured it would, say, ask me to put in new filament, but it didn't, so I just stuck the filament in while it was starting. It made it about halfway through the first layer before anything started coming out. I stopped that print after 2 or 3 layers because it clearly wasn't working, ran it again, and everything was fine.

I later switched to Prusament PETG, and had a basically identical experience. I had to scrap the first print after the plastic didn't come out.

Then later when switching colors and had the same thing happen yet again I figured I should investigate, and sure enough, it looked like the new IR filament sensor was always reporting as filament in place, no matter whether filament was there or not. Guess it would have been nice if the unload procedure would have warned about that or something?

To troubleshoot I followed https://help.prusa3d.com/article/43mduc4zdn-filament-change-prompted-at-the-beginning-of-the-print to take things apart. Interestingly, as soon as I loosened up the screws holding the extruder motor in place, the sensor started reading as no filament and moving the switch made it register correctly. Basically zero travel was required for the sensor to register with the extruder off, which I figured was the problem.

I shaved off a few slices from the lever arm with a pocket knife, right at the surface where it first occludes the IR sensor. This gave the sensor a bit more travel before it registered. I re-assembled everything and now I finally see what the auto-loading workflow is supposed to look like. Nice!

What's the right mechanism to notify Prusa that maybe the dimension need to be tweaked on that part?