HMS 0300-9100-0001-0007: chamber heater 1 sensor open circuit
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 0300-9100-0001-0007 means the temperature sensor on chamber heater 1 reads as an open circuit. The controller has no way to know how hot that element is, so it refuses to run it. PLA and PETG are unaffected; what you lose is the warm chamber that ABS, ASA and filled nylons depend on.
Affected machines: X1 series. This sensor sits on the heater itself rather than in the chamber air, which is why its failure disables the heater specifically rather than just distorting the chamber reading.
Where to buy
Connector, lead, then sensor
Open circuits start at connectors far more often than at sensors. The heater assembly gets warm and cold on every print, and thermal cycling works connectors loose over months. Unplug, look at the pins in both halves, and reseat firmly before measuring anything.
Then measure at the sensor rather than at the board, so you know which side of the connector the break is on. Around 100k ohm at room temperature is healthy on these machines. Open at the sensor means the sensor; open at the board with a healthy sensor means the lead.
Position matters when you fit a replacement. A sensor mounted even a centimetre from where the original sat reads a different temperature, and the firmware assumes the original location when it decides how hard to drive the element.
Chamber heating unavailable and the printer reports the heater 1 sensor as open circuit
Loose connector, a broken lead, or a failed sensor
- Power off at the wall and let the chamber cool fully before opening it.
- Locate the sensor on chamber heater 1 and note exactly how it is mounted before disturbing it.
- Unplug it and measure across the pins. Around 100k ohm cold is healthy; open confirms the fault.
- If the sensor reads healthy, reseat the connector and measure again at the board end to isolate the lead.
- Inspect the lead where it passes anything hot or anything that moves.
- Fit the correct replacement for your model in exactly the original position and orientation.
Print PLA and PETG while you wait for the part. Neither uses chamber heating, so the machine stays useful for most work rather than sitting idle.
The over-temperature version is chamber heater over-temperature, and the chamber air sensor fault is chamber sensor open circuit. Our pages on enclosed printers and ABS and ASA explain what you lose.
HMS 0300-9100-0001-0007 FAQ
Can I print meanwhile?
PLA and PETG, yes. Materials that need a warm chamber should wait.
What should the sensor read?
Around 100k ohm at room temperature, falling as it warms.
Does mounting position matter?
Very much. Fit the replacement exactly where the original sat, or the readings will be wrong in a new way.
Is this the same as the chamber air sensor?
No. This one is on the heater; the other measures the chamber. They have separate codes and separate parts.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
