Hello Community,
I struggled for a long time with an issue where my AMS displayed a static or flashing red LED, causing my print to stop. The problem usually occurred after a filament change, but sometimes it also happened during printing with the same filament, although in that case, it was just a static red LED. This wasn’t as frequent, though. The biggest issue for me was the filament change. It got so bad that I had to manually intervene with every single filament swap—either by pulling the filament a bit (sometimes with more force) or by slightly pushing it to the left at the feeder. For me, the issue occurred most often in slots 0 and 2, occasionally in slot 3. Interestingly, slot 1 never let me down! 
I decided to investigate the problem, so I disassembled the AMS to take a closer look at the mechanics. I have the version with the Hall sensor.
You can check which version of your AMS you have at the link below.
I disassembled it to the point where I had the small magnet in my hand.
Dismantling at the links Below.
Step1:
Step2:
I re-magnetized it using a magnetizing tool, as shown in the image. This is something that many people might have in a small tool kit designed for small device repairs.
After this fix, I was able to resolve the issues with slots 0, 2, and 3.
Maybe this could help some of you as well!
Happy printing! 