P1S, bought it and the ams refurbished from Bambu, has worked fine until last night. Initial troubleshooting I tried to push the filament up to the extruder, would not go. Tried a couple of different spools, same results. Watched a video about how to remove a piece of filament oin the feeder so I disassembled the ams. Did not find any scraps of filament.
It seemed that the filament would not pass the feed wheels in the ams, so I removed the screws that hold the idler wheel in place, and I was able to push the filament through easily. Again no scraps of filament. Used dust-off to blow everything out. Removed the gear-motor assembly, everything turns freely. Reassembled, found that filament has a hard time getting between the feed wheels, almost like the wheels are a little too close together. Once the filament is between the wheels, it will move easily. I can turn the gear with my finger and move the filament back & forth.
Put the ams back together and mounted on top of the printer, will not feed the filament.