Printing without MMU3 once MMU3 is installed
I have installed the MMU3 on a MK3S+, and sometimes I want to print directly on the printer without using the MMU. I used an external spool holder, disconnected the PTFE tube to the extruder from the MMU, and disabled MMU in the settings. I noticed a few odd behaviors:
1. I can not autoload filament, I have to manually move the extruder motors to load the filament
2. The filament runout sensor doesn't seem to work. Even without filament it just keeps running.
Other than the above, the printing does work.
Does installing the MMU mean the filament sensor in the extruder no longer works without the MMU? Is what I want to do a supported use case?
RE: Printing without MMU3 once MMU3 is installed
The MMU is a kludge, you sacrifice a good deal to get the multi-color printing by sharing the same extruder. I don't know if you ever print with tpu, but it was such a hassle to use tpu with the MMU-enabled printer that I simply didn't do it and left all the tpu printing to the non-mmu printer. When the MMU is in operation, you're using both the sensor in the extruder and the finda in the MMU(at least this was how it worked on MMU2S). The firmware 3.x that's in the MMU3 also was installable on the MMU2S, and I had a little bit of experience with it before removing the MMU from my MK3S during the upgrade to MK4. To be honest I don't think I operated it in a bypass fashion after the installation of firmware 3.x. Prior to 3.x, you actually had to unplug the power from the MMU to get the same effect as turning it off in the menu in 3.x+ But as I recall autoloading certainly didn't work when the MMU was disabled(off in my case).
I had two MK3S printers that got updated to MK4. One of these had the MMU2S on it and I chucked it during the upgrade. I have a 5 extruder XL now so the likelihood I'll ever do an MMU again is small.