After a filament run out, the AMS has a problem advancing the filament from the new spool. I load the spool and insert the filament, the AMS grabs it and starts advancing it, but almost immediately rolls back. It then tries again and again - forward a couple inches, back, forward, back - for a long time. To get it to stop, I have to time the filament pull back and manually pull it all the way out. It then runs for another 10 seconds or so trying to back out, then shows an error about not filament.
I first thought it was the filament and tried a different spool. No luck. I then assumed it was some sort of blockage, so I canceled the print and took everything apart but did not find any problems. The next time it happened, I swapped in the AMS from my X1C to continue the print, and then again took apart the problematic AMS and found no blockages. I put that AMS on the X1C and have had not any problems for a week or two.
Today it happened again, on the P1S, with the AMS that was originally on the X1C, in the same spool slot #3. I turned the printer off and on and continued the print and the filament loaded and everything was fine after that.
No idea what’s going on.
So, it seems to be related to the P1S, not necessarily the AMS unit. It only happens when filament runs out during a print, otherwise I’ve had no issues loading filament. The P1S is about a year and a half old, the AMS that was originally on the P1S is about 6 months old, the AMS from the X1C is about 2 years old.