HMS 1A00-0100-0002-0020: A Hotend Is Already Installed in That Slot
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HMS 1A00-0100-0002-0020 means the rack went to place a hotend into the slot it names and found one already there, and it asks you to remove the existing one before continuing. The wording is the same as another code in this family, and the fix is the same: clear the bay and let the check re-run.
If you came here having searched the exact code, the useful information is that nothing about it is unique.
Where to buy
Clear the slot, then continue
With the machine idle, take the unexpected hotend out, note which bay it belongs in, and store it with its mounting faces protected. Then continue. Never force a placement into an occupied bay, because the rack will press one hotend against another and the damage lands on the mount rather than the plate.
Why the machine was surprised
It keeps a record of which bay holds what. Hotends moved by hand between prints, two swapped around, or a sequence interrupted partway all leave that record out of date. None of those is a defect, and all of them produce this message on the next placement.
The identically worded sibling
This code and HMS 1A00-0100-0002-0004 report the same condition in the same words. Bambu raises them from different points in the swap sequence, which matters to support rather than to you: the recovery is identical. Note which number you actually saw if you open a ticket, and otherwise treat them as one fault.
When HMS 1A00-0100-0002-0020 really means something else
If every bay is occupied rather than just the targeted one, the honest message is the capacity code HMS 1A00-1300-0002-0001. And if the machine cannot confirm either end of the move, you get HMS 1A00-0100-0002-0022, which is a state-recovery problem rather than a single blocked bay.
The habit that prevents all three
Return every hotend to the bay it came from, label the bays, and finish a swap before powering down. Hardware background is in 3D printing hotends.
HMS 1A00-0100-0002-0020 FAQ
Is this a different fault from the other code?
No. Same condition, same fix, raised from a different stage of the sequence.
Can I move the hotend myself?
Yes, with the machine idle. Lift rather than lever.
Will the print survive?
It stops before the move, so clearing the bay and continuing costs you nothing.
Should I report it?
Only if it recurs with a correct slot map. Then the code number is worth quoting exactly.
LayerWalker
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