Hello dear bambu forum,
Since this morning, the filament buffer is crunching continuously. The noise is more like a squeak and accordingly excites my nerves. Does anyone have any experience with this?
Same issue here after replacing the MC board fan.
I noticed that the PTFE cable passed above the spool holder. I made it passed from below and the noise has disappeared.
Sorry for my bad English 
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You’ve saved my life and my sanitiy! Thank you SO much. 
Thank you, This fixed my issue!!!
Worked perfectly, no more squeak! Thanks
I just woke up and noticed that the auto refill to the next spool didn’t start, filament was stuck in the tubing. Had to watch a couple of other videos on how to disconnect everything. I’ve only had my machine for a couple of weeks. Put everything back together. Noticed the squeaking. And sure enough, I too had the tube above the spool holder arm. moved it below. Stopped squeaking instantly. Thank you.
I Recently swapped out the ptfe tube coming from the buffer to the printer, it was a couple inches longer. Squeak started and I couldn’t figure it out, other than it coming from the buffer. Thank you! Just lifted the tube and lightly zip tied it to the ams cable to keep it in place and the squeak stopped completely. With the printer in my bedroom (hardly any other space until I move) this kept me up at night to where I’d have to pause prints just to sleep.