I have a relatively new Mini (a few weeks old) and yesterday it started under-extruding partway through a print. It first happened a couple hours into a fairly complex print. After that it was under-extruding on simple prints too.
This morning, I switch cura over to the default settings and tried again. About fifteen minutes into a relatively simple print is started happening again. But for the first 15 minutes, I had no trouble.
If I have the Hotend heated to 200 and I manually extrude some filament (10), the mechanism seems to lock up periodically (I can see the large gear stop temporarily). If I release the tension holding the filament to the extruder wheel, the mechanism no longer binds. But there is some clicking noise in at some points (not motor noise).
I’m printing with 3mm PLA Filament from ic3d and removed about a foot of material to no effect. I’ve gone through the nozzle clearing process a few times and get the expected shape at the end of the filament with the exception of the tiny 1mm extruded bit at the tip.
If the gear mechanism does need oil, do I just apply it to the bearing on the front of the mechanism? If it needs cleaning, do you have a guide taking it apart?
Any other ideas?