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
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.
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.
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.
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.
I’m having same issue. Ams 2 pro slot 4. I can swear nothing stuck anywhere. I took it all apart. Damn I guess maybe I have to do it again. I already opened a ticket with bambu. They might send me a new filament feeder.
New poster here. Just reading some of the failure to feed posts and want to share what I found and resolved on my issue today. I was having a failure to feed on slot 1 of the AMS 2 pro, but it would work when I applied some force to the filament and felt as if there was an obstruction. No problem with the PTFE tube. Removed the central hub and found that the issue was just where the filament leaves the tube as it enters the hub; there is a small metal piece that has a ramp shape to it where the filament hits it and underneath there is a spring. All 4 ports have the same metal piece, which is actually a magnet as underneath there is a small PCB which I’m guessing has a hall sensor of some kind. This was where I was getting an issue. The magnet on port 1 needed more pressure to move it so that the filament could pass. I removed the motor and then the 5 screws that held the upper part of the hub from the bottom. Once done I removed the PCB over the 4 port magnets. At this point I did not realize they were magnetic and on removing the board the all jumped out and stuck to one another along with their springs. It was a fiddly hassle putting them all back and I had to place them one at a time and hold my thumb over each as I got them in. Getting the PCB over them without it all falling apart again was a pain too but once done and the PCB was safely screwed down again, I tested the action and the port 1 magnet now felt like it was moving more freely. Put everything back together and tested with a roll of filament. No more issues. The filament loaded correctly with no obstruction back and forth like before. I dont know if this is a permanent fix as it seems crazy that it would fail in the first place but only time will tell.
