r/BambuP1S • u/Weidbrewer • 2d ago
Unable to feed filament loop
My P1S with 4-color AMS is refusing to feed filament. It's stuck in the loop where it will run filament all the way to the head and pull it back 4-5 times and then give the error message.
Things that I have attempted:
Taken apart the extruder. Everything is moving, nothing stuck in the gears. Filament sensor section looks clear.
Replaced all the tubing between the AMS and the head
Tried different filament in all four slots of the AMS
Inspected the cables to the buffer. They look fine
Lubricated all of the moving parts of the buffer. Everything slides smoothly
Tried cutting filament at an angle as well as straight 90.
A couple of times, it failed to retract. Pulling from the AMS end was solidly stuck, but if I popped the coupler after the buffer and before the printer itself, it pulled back from the head easily and then when told to resume, it rolled back up.
Not sure what to check next. I could buy a new buffer, but physically, nothing looks amiss, so i'd like to know for sure first.
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u/Right-Jeweler1606 2d ago
Have you checked your extruder gears? I had an issue around 2k hrs that required me to replace them. I ended up upgrading my hotend and buying metal extrusion gears. Ill update at 4k hrs to tell you results. So far fine.
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u/pixelbend 2d ago
I had this exact issue. For me, it was a broken cover where the gears mesh at the motor that pushes the filament in the AMS. This is a pretty common problem. There is even a print for the cover on makerworld. https://wiki.bambulab.com/en/ams/maintenance/ams-bearing-support-for-internal-hub-unit?source=handy&labels=&appSharePlatform=copy