Factory built MK4S extruder clicking
I got my factory assembled MK4S about 4-5 weeks ago. I set it up and it printed without drama. After a week or so of printing I noticed a random intermittent clicking noise coming from the extruder. It did not seem to affect print quality, but I did notice some odd layer lines on silk PLA print of a model I've printed several times before. I have tried all the usual troubleshooting steps. I've increased/decreased nozzle temp. I've adjusted the tension in both directions. I've done cold pulls. I've even changed the entire nozzle from a .4 mm to a .6 mm with no difference in the symptom. I've just tried it with filament inserted and the tensioner completely open and I still hear the clicking noise when it's feeding filament. Since I frequently run my 4 Prusa printers at the same time and the clicking sounds lot like a partial clog, it's driving me nuts. I also have a kit built MK4 and it's never made this noise.
RE:
I believe I've solved the problem. I ran through the extruder gear calibration procedure. I've now done 2 prints since then and have not heard the noise at all. I didn't bother doing that calibration when I got the printer because it says you don't have to if the machine was factory assembled.