HMS 0300-0A00-0001-0001: Heatbed Force Sensor Sensitivity Too High
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HMS 0300-0A00-0001-0001 means the sensitivity of one of the heatbed force sensors is too high. The sensors under the bed detect the nozzle touching down, and one that is too sensitive triggers before real contact, which makes the measured bed position wrong rather than missing.
Over-sensitive is the more dangerous direction, because the machine still gets an answer. It is simply the wrong one.
Where to buy
Look for anything preloading the bed
A sensor reads force, so anything already pushing on the bed shifts its zero. A cable routed under the plate, a chip of purge wedged in a corner, or a plate seated on debris all show up as high sensitivity. Lift the plate and look before you touch any screw.
Check the mounting screws, properly
These sensors sit in a clamped stack, and a screw a quarter-turn tight changes the reading. A hex key set that fits properly lets you check each one at the same feel, which is the whole trick: consistent, not maximum.
Confirm the gap rather than guessing
A feeler gauge under each bed corner tells you whether the stack is sitting evenly. An uneven stack loads one sensor more than its neighbours, and that is exactly what a sensitivity complaint describes.
Then stop the screws moving again
If the same sensor drifts out after every few prints, blue medium-strength thread locker on the mounting screws is the answer rather than more torque. Over-tightening into a bracket is how a sensitivity fault becomes a stripped thread. The acceleration sensor on the same bed has its own faults, starting with HMS 0300-1B00-0001-0001.
How HMS 0300-0A00-0001-0001 pairs with its opposite
The mirror case is HMS 0300-0A00-0001-0003, where sensitivity is too low and contact is detected late or not at all. Reading which direction the message names tells you whether to look for preload or for a loose stack.
What it does to your prints
A false-early touch means the nozzle stops short, so the first layer is high and does not stick. The mesh that gets built from these readings is explained in bed levelling mesh, and the general sequence in calibrating a 3D printer.
HMS 0300-0A00-0001-0001 FAQ
Can I adjust sensitivity in software?
No. You remove what is loading the sensor and make the mounting even.
Which sensor is 1, 2 or 3?
The Wiki shows the positions. Check all three while you are in there.
Does a dirty plate cause it?
Debris under the plate does. Dirt on top affects adhesion, not force.
Will recalibrating clear it?
Only after the mechanical cause is gone. Otherwise it stores a wrong zero.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
