Failed to pull back filament error - Spool is unwinding (Pictures)

Bambu Lab AMS
21

At the risk of wasting more of your time, have you tried removing the internal hub and disassembling it? It’s remotely possible there’s a small piece of filament stuck in it causing the sensors to think there’s still filament loaded in the AMS past the hub towards the printer. This would affect all slots if so. This link shows how to do it if you haven’t yet. I’ve never had to do this so can’t offer much help, myself I’d be inclined to try it to confirm it’s clear while you wait for BL to help.

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Me too, very irritating!

1 Like
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I’ll give it a try. Thanks for the tip!

24

I had the same issue with one of the four filaments in my AMS 2 Pro. I received it along with my P1S and all Bambu filaments about 2 weeks ago and it’s been performing flawlessly until today. My fix was to blow it out with compressed air:

  1. Remove the PTFE tube going into the hub, the one from the AMS (push on the black ring while pulling on the tube).
  2. Insert the filament. When it unwinds/unspools from the AMS remove the filament from the AMS. The AMS will continue to unwind.
  3. Blow compressed air into the AMS filament inlet as it’s turning. I used 20 #'s of shop air but a small can of air would probably be the wiser choice.
  4. Blow compressed air into the PTFE tube.
  5. Repeat step 3 above.
  6. Reinsert the PTFE tube into the hub.
  7. Reboot the printer (power off then back on).
  8. Reload the filament.
    If this doesn’t solve it then repeat the procedure. It worked for me.