Possible piece of broken filament stuck inside my AMS?

Bambu Lab AMS AMS 2 Pro
1

I have an AMS 2 Pro on a P1P.

If I unplug the AMS and print using the external spool everything prints perfectly, not errors, no issues.

If I plug the AMS in and try to print the second spool runs wildly, it pulls the filament back and keeps going even though the end of the filament has come out of the feeder and is flapping around as the spool spins.

It eventually brings up the error message “AMS failed to pull back filament”.

When I try to feed the filament back into the AMS it gets as far as the little 4 way PTFE splitter and won’t go any further. The filament never enters the PTFE tube that comes out of the back of the machine.

I’ve checked the PTFT tube coming out of the back of the AMS and it’s completely empty. I checked the filament buffer and it’s empty, and I checked the tube going to the hot end and it’s empty.

If I remove the AMS and then print using an external spool it runs perfectly, so the issue must be inside the AMS somewhere. All that I can think of right now is that there’s a fragment of filament stuck

right in the splitter unit.

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I tried pushing it through with some filament from the front, and removing the tube at the back and pushing it that way, but I can’t seem to get anything pushed through.

Does anyone have any clues?

This happens when I start to print using the AMS, regardless of which spool I use, it tries to retract the spool 2 and then stops, so I’m guessing that it’s the tube for spool 2.

2

You can open it and check whether a filament is stuck. Disclaimer: May be look a little different in the video from yours, but the approach is basically the same. I’ve only found videos of AMS, not AMS2.

Here is one possible solution without opening it:

Here’s how to open it:

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3

fortunately this didn’t require dismantling the ams, there was a short segment of filament right where one of the tubes inside ended. I pressed the release button, removed the tube and then poked out the segment. no tools needed. I just had to wade through a bunch of stuff before I found out that there was a release button.

obvious when you know what to look for.

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4

Yeah. AMS 2 pro doesn’t require full disassembly, tubes are accessible with quick release feature :sweat_smile:

It looks like debris/dirt or some sort of Schmutz. :winking_face_with_tongue:

5

I’d just installed a snag cutter and hadn’t properly tuned it, so it sliced a short section of filament when I changed the spool without realising and it blocked the tube for some reason.

is there a gate or something similar where the tubes meet?

I tried pushing it through from both sides but couldn’t budge it. yet when I disconnected the tube it slid right out.