Just a report, you might experience the same problem at some time.
I bought a P1S combo with the AMS (version without heater/dryer function) in June 2025. I have only ~640 hours print time.
Main used filament is PLA Basic and ABS Basic, 90% I use original BambuLab filament. Only occasionally I used eSUN filament.
Last Sunday the AMS was suddenly not able to push filament to the print head anymore from any of the 4 slots.
Filament got stuck at random positions, sometimes before the external buffer, sometimes before it reached the P1S, sometimes before it reached the print head. Printing from external spool worked without problems.
Checking the PTFE tubes, the external buffer and the print head, I found no left over broken filament or other blocking damages.
Disassembling the AMS I found that the internal filament hub was broken. Literally broken, as the plastic part of the internal filament hub was broken. A part that hold the extruder wheel hung loose around, just hold by its cable and a small plastic part was on the bottom of the AMS enclosure:
I got a replacement from the local BambuLab certified dealer I bought the combo. They were super fast with their support and I got the replacement within 2 days.
After replacing the internal filament hub and testing (all works again), I disassembled the broken filament hub and was surprised of what I found inside. There is a lot of filament dust inside, including covering the extruder wheels.
I guess all of this created so much friction that the plastic part couldn’t stand the stress anymore.
Anyone has an idea how to keep this internal filament hub clean? Disassembly of the filament hub for cleaning is not possible, it seems to be impossible to re-assemble the plastic parts.
