Fixing a Bambu Lab X1C Error: "Extruding filament failed. The extruder might be clogged."

My 3D printer broke.No matter what I tried, I couldn't get past this error: "Extruding filament failed. The extruder might be clogged."I took apart the extruder gear assembly to check for clogs:I inspected the little magnet on the filament sensor and tried flipping it around (a tip from a comment on the Bambu Labs forums):I tried replacing the 0.4mm nozzle with a 0.6mm nozzle, but that didn't help. And I confirmed that I was able to manually push through filament by hand when the nozzle was heated up.Then I ordered a replacement gear assembly and filament sensor and waited for those to be delivered. I installed them, and still got the same error! 0:00 /0:06 1× f Finally, I figured it out. For some reason, a screw on the back of the printer had become impossible to remove. It's one of the screws for the AMS internal hub unit. I had cracked that unit while trying to get the screw off, and this had caused a small kink in the PTFE tube.Apparently, the printer is very finicky and doesn't…