Extruder popping and filament unloading during print
I recently acquired a MK3 in an unknown condition. Decided to start off with a new hotend, updated firmware, performed a factory reset, and have performed all axis calibration tests. When performing the built-in first layer calibration test, it asks to load and then verify the "filament is extruding and the correct color" (or something of this nature) to which I click "yes" it then proceeds to print the zig zag lines and just before it begins making the small rectangle of lines to test adhesion to each other, the extruder starts popping and the filament feed stops but the bed/hotend continue to move.
I tried several times with the exact same result. I then tried printing the "stress free first layer calibration" stl from the Prusa website and it immediately begins with the popping and no filament feed. I held the filament tight between my fingers (as not to slip but did not push or pull filament) and it is actually unloading when the popping is occurring. The filament is going higher and higher as if the stepper motor is reverse polarity (unloading instead of loading).
Can anyone provide any assistance on this one? I have searched and have not found anything similar to this.
RE: Extruder popping and filament unloading during print
Check that the extruder gear is not loose and is aligned correctly. If you don't how, look for the assembly manual for the printer and it will explain it. It may be more of a clicking than popping. The assembly manual may help with checking everything else out to make sure that nothing has come loose or is damaged.