HMS 1A00-1200-0002-0003: Rack Calibration Result Exceeded Travel Range
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HMS 1A00-1200-0002-0003 means the calibration produced a number outside the range the rack can physically move, and Bambu asks whether the rack structure is deformed. An impossible result means the machine is measuring something that is not where the geometry says it should be.
This is a stronger statement than a failed measurement. The machine got an answer and rejected it as nonsense.
Where to buy
Check the rack for deformation, as asked
With the power off, sight along the rack and compare slot positions against each other. A rack that has taken a knock, or has had a swap forced against a latched hotend, bends at its weakest point rather than breaking. Lay a straight edge across the mounting faces; a dial indicator on a magnetic base gives you numbers if sighting is ambiguous.
Then check the mounting
A rack that is straight but mounted loose moves under its own weight, which produces the same impossible measurement. Work along the fasteners and confirm each is tight. A fastener that keeps loosening wants a drop of medium-strength thread locker, not more torque.
Then rule out a bad reference
Calibration measures against something. If that something has moved or is unreadable the result is garbage, and garbage can land outside the travel range. The unreadable-image case is HMS 1A00-1200-0002-0001, where cleaning is the fix, so rule that out before concluding the rack is bent.
What HMS 1A00-1200-0002-0003 rules out for you
It tells you the problem is not a marginal measurement. A slightly dirty surface produces a slightly wrong number, not an out-of-range one, so this code points at geometry rather than at cleanliness. Homing failures with the same root cause show up as HMS 1A00-1100-0002-0002.
After any correction
Re-home, re-run the rack calibration, and check the result is inside range before printing. The general sequence is in calibrating a 3D printer, and the machine itself in the Bambu Lab H2D review.
HMS 1A00-1200-0002-0003 FAQ
Can a bent rack be straightened?
Not reliably. Positional accuracy is the whole point of the part, so a deformed one is a replacement.
What bends a rack?
Force. A swap pushed against a latched hotend, or a knock during transport or maintenance.
Could it be a software fault?
Rarely, and a firmware update is free to rule out before ordering a part.
Is it safe to print meanwhile?
Single-tool printing may be fine. Swapping is not, because slot positions are what failed.
A rejected measurement is not always an impossible one. HMS 1A00-1200-0002-0004 is the height step specifically, and Bambu names jamming rather than deformation.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
