After doing some repairs and upgrades on my Ultimaker Original, I found my temperature readings to be weird.

The reading is not incorrect, as long as the temperature is above 110°C. When the real temparature is below 110°C, the sensor will always read 110°C, with only subtle changes around 0.1°C.

This will cause the printer to abort heating, because it does not see a change in temparature for the first 30 seconds (when the temperature is below 110°C).

Pronterface Tempearture Readings

Here you can see a screenshot of Pronterface, showing how the temperature (blue line) starts increasing when my printer already aborted heating (violet line).

I am certain that the reading is incorrect because at the beginning the hotend actually feels cold to touch.

I am also certain that the reading above 110°C is more or less accurate.

  • What could this be caused by? What parts should I replace?
  • If I should replace the TC2, will a TC1 do too? I can't seem to find any store selling the TC2.
  • If I should replace the sensor, what kind of sensor should I search for?
  • Or is there a drop-in sensor-chip-combination that I can buy?
  • $\begingroup$ What were your upgrades? $\endgroup$
    – Trish
    Aug 27, 2018 at 14:13
  • $\begingroup$ A lot of different ones, new extruder, new heater, new (but same) chip. The temp sensor is still the same though, so I suspect it got damaged during my migration into the new heater block. $\endgroup$ Aug 27, 2018 at 19:33
  • $\begingroup$ At first you should check the temperature sensor. See if the resistance increases in proportion to the temperature. Then it might be a good idea to find the component causing the problem by swapping them with the original one by one. $\endgroup$
    – Klaus D.
    Aug 28, 2018 at 8:15
  • $\begingroup$ The temp sensor is original though. $\endgroup$ Aug 29, 2018 at 15:14
  • $\begingroup$ Maybe the temperature sensor isn't making proper contact with the part it's meant to be measuring, until said part has slightly expanded? But a damaged sensor would be my first bet. $\endgroup$
    – Firedrake
    Oct 4, 2018 at 10:06

1 Answer 1


The fact that the temperature reading stays steady while heating and changes once it stops heating makes me thing that you might have a short between your heater wires and sensor wires or somehow have them interconnected. Especially if it shows the same temperature when it's actually below 110°C and heating but shows correct when not heating. I would try to separate the heater wires from the sensor wires and make sure they are not touching, also check that the sensor wires are not touching the heating block.


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