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I recently bought a High-Precision (400 °C) Revo Hotside with the intention to use it on my upcoming Voron. In the meantime, I wanted to give it a go and use it on my Prusa, if for nothing else, then at least to print some missing Voron parts. Also, it's still in the "hassle-free return" period, so I'd love to test it without replacing the thermistor or altering it in any other way.

"Sadly", PT1000 is not a drop-in replacement for Semitec 104GT thermistor Prusa is using. It operates in a similar resistance range and should be supported by the Einsy Rambo board, but it works with a higher max temperature*, and has a different resistance-temperature function.

I was thinking about switching my Prusa to Klipper, but I admit it is a daunting task I don't want to attempt until I have my next printer up and running. So is there a simpler way?

* PT1000 works up to 400 °C with precision, some more is still safe when 104GT is up to 300 °C.

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  • $\begingroup$ Still waiting for an answer telling me how, instead of one telling me not to. $\endgroup$
    – Mołot
    Commented Jan 16 at 20:07

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There's no reason you need Klipper; in principle you could rebuild Marlin (stock or Prusa's version of it; you probably want the latter) reconfigured for a PT1000. However, that's a fair amount of work and chance for something to go wrong if you're not familiar with doing it. Unless you're actually trying to use extrusion temperatures above 280°C or so, you will get no benefit whatsoever from the PT1000. Above that, the PT1000 will give somewhat better PID control (more stable temperature). If you don't care about perfect temperature stability, the stock thermistor will work up to at least 320°C, maybe 330. But to get access to any of these temperatures you will already need custom firmware, since Prusa has the max temp capped well below that.

If you just want to test the hotend, but don't want higher temperatures, you can just put a standard 100k NTC thermistor like the one you have on the new hotend, and it should work with the Prusa firmware unmodified.

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  • $\begingroup$ One of the reasons is that my current thermistor is unstable at 250 when printing ASA / ABS. $\endgroup$
    – Mołot
    Commented Jan 12 at 20:32
  • $\begingroup$ @Mołot: That's an underpowered heater cartridge not a thermistor problem. The issue with NTC thermistors is that once you get hot enough (low enough resistance), there are too few bits in the ADC measurement for the MCU to really tell what's going on with fine changes in temperature. But that does not happen until way above 250. So just going to the new hotend with a decent cartridge in it (or even just putting a 50W or 60W cartridge in your existing hotend) will probably solve your problem. $\endgroup$
    – R.. GitHub STOP HELPING ICE
    Commented Jan 12 at 20:34
  • $\begingroup$ I'm inclined to believe you. Still waiting for an answer here. But I don't like the idea of dismantling pretty expensive heating assembly before I'll test it as-is, and I'd love to test it during its hassle-free return period. $\endgroup$
    – Mołot
    Commented Jan 12 at 21:15
  • $\begingroup$ I would just put a <\$5 65W cartridge (I got 3pc/$10 on Amazon) on your old hotend for the time being. $\endgroup$
    – R.. GitHub STOP HELPING ICE
    Commented Jan 13 at 21:57
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    $\begingroup$ Don't forget to tune the PID values when installing a higher Watts cartridge, I got instability using the old values after installing a new one. $\endgroup$
    – 0scar ♦
    Commented Jan 14 at 9:27

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