HMS 0300-0100-0001-0005: Heatbed Temperature Control Issue, Replace the AC Board
LayerWalker is a participant in the Amazon Services LLC Associates Program. We may earn a commission when you buy through links on our site, at no extra cost to you.
HMS 0300-0100-0001-0005 means a heatbed temperature control issue was detected and the heating module may be damaged. Bambu tells you to power the printer off immediately and follow the Wiki to replace the AC board. The word immediately is doing real work in that sentence, so act on it before anything else.
Mains-voltage heating faults are the one category where the right first move is the switch, not the menu.
Where to buy
Power off at the switch, then unplug
A control fault means the printer can no longer be sure what the bed heater is doing, and a bed heater that will not turn off is a fire risk rather than a print-quality problem. Down at the switch, then out at the wall, then walk away for ten minutes before you open anything.
Measure before you order parts
With the machine unplugged and cool, a multimeter across the bed heater and the thermistor leads tells you whether the fault is the heater, the sensor or the board. A reading turns a guess into a part number, and support will ask for exactly this.
Use the right driver on an AC board
These boards sit behind small fasteners in tight brackets and carry mains wiring. A precision driver set that actually fits the heads is the difference between a clean swap and a rounded screw on a live-voltage assembly you cannot leave half-apart.
Earth yourself before touching anything
An anti-static wrist strap costs a few dollars and protects the control electronics you are about to handle. Static damage does not announce itself at the time; it shows up as a board that works for a week. The bed sensing chain that depends on this board is described in bed levelling sensors.
Why HMS 0300-0100-0001-0005 is not a calibration problem
Bed temperature faults that are about control rather than damage report differently — the limit-exceeded case is HMS 0300-0100-0003-0008 and it is informational. This code names damage and names a part, which is unusually direct for an HMS message.
What to tell support
Quote the code, say the machine is powered off, and give your meter readings. Related heating faults in this family are collected under HMS 0300-0100-0001-0001, and bed basics are in bed levelling.
HMS 0300-0100-0001-0005 FAQ
Can I keep printing carefully?
No. The message says power off immediately and it means it.
Is the AC board always the fault?
Not always, but it is the part Bambu names. Measure the heater and sensor first.
Is this covered by warranty?
Ask support with the code and purchase date. It is a component failure, not wear.
Can I replace it myself?
The Wiki documents it, but it is mains wiring. If that sentence worries you, let support do it.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
