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When reassembling the AMS internal hub magents, every source calls your attention to pay attention to the right “direction” or “polarity”. But what is right? I assume that if I use auxilliary magnet, then the auxiliary magnet shall attract the hub magnets in position and that will be “right position”. But this is not clear.
In the Bambu Lab AMS (specifically the filament buffer or sensor assemblies), the correct north-south (N-S) orientation of internal magnets is critical. For components like the AMS filament buffer, the side marked or highlighted with a red line/indicator must face the right side or represent the North Pole (N) as specified in official repair diagrams to avoid sensor loss errors. [1, 2]
Assembly and Orientation Details
Filament Buffer: Align the magnet so the red-marked side or North pole indicator points to the right. Incorrect orientation triggers the sensor error HMS_0700-4000-0002-0001 (signal lost). [1, 2]
Hub and Feeders: Magnets in the AMS tracking and hub pathways must have their free-moving or sensing faces oriented identically to how they interacted before removal; flipping them breaks the magnetic trigger threshold for the hall effect or position sensors. [1]
Verification: If reinstalling a loose magnet, check the Bambu Lab Wiki maintenance guides for your specific sub-assembly (like the buffer or feeder connection board) to match their exact N/S layout diagrams.
It sounds like the ones used with hall sensors need to be installed as they were originally to work correctly. If there isn’t a set orientation there may be some reassembly and testing in your future.