False bed temp reading
When the printer is running for a couple of hours, the displayed bed temp is way to high (about 90 C when the bed is at ambient temp). This cause a max temp alert, because the printer thought the bed temp had exceeded 110 C (even though the bed was probably around 60 C).
I check all the wiring and thermistor resistance is within specification. No visible damage anywhere.
I left the printer alone over night and everything went back to normal. And after a couple of hours of printing same thing again.
Anyone seen this behaviour? The printer is not even a week old.
Many thanks,
Daniel
RE: False bed temp reading
I suggest that you contact support via the chat on the eShop page.
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Chuck H
3D Printer Review Blog
RE: False bed temp reading
Already did that. He somehow concluded that the bed power cable is faulty and send me a new one. Will arrive tomorrow.
I'm skeptical that this is the problem, I could not find anything wrong with my cable.
Support came to this conclusion, because I measured the heat bed resistance at 5 Ohm and not not between 6.5 and 7 Ohm. But I think that has nothing to do with the cable!
RE: False bed temp reading
@kuchenloch
Well, tomorrow you will know. I have not seen a faulty bed, but it has been suspected by many.
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Chuck H
3D Printer Review Blog
RE: False bed temp reading
@kuchenloch
Maxtemp can also be triggered by a short circuit of the thermistor line. In this case, the internal resistance briefly approaches 0.0x ohm's and thus falsifies the calculated result of the bed temperature.
If the Prusa suggestion does not help, I would replace the thermistor incl. wires, because the wires in the area between the heating bed and Einsy connection tend to break.
good luck!
wbr.
Karl
Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen.
RE: False bed temp reading
I checked the connector on the board and measured the thermistor resistance. I could not find anything wrong there. A short circuit would lead to a constant max temperature reading, in my case it's more like an offset of about 70 degrees (I let the bed cool down to ambient and the display showed about 90 C). And then I switched the printer of over night and the next morning it went back to normal on its own.
RE: False bed temp reading
So far I have not replaced the connector with the one Prusa sent me, because I did not encounter that error anymore. Printer just works fine now.
False Bed Temp Reading
Im having the same issue on a pre-built printer that is about 2 weeks old. When I turn it on from resting overnight it shows the bed temp to be ~90 when it is cold to the touch. Any recommendations on how to solve?
chat
Im having the same issue on a pre-built printer that is about 2 weeks old. When I turn it on from resting overnight it shows the bed temp to be ~90 when it is cold to the touch. Any recommendations on how to solve?
Check all your connectors to your controller board. If that does not work, try a factory reset. Lastly, consider contacting support via chat on the shop.
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Chuck H
3D Printer Review Blog
RE: False Bed Temp Reading
One thing to consider is the environment's temperature where you keep the printer. If the ambient temperature is low enough, it is possible that the measured temperature underflows and is then seen as max temp. I have seen IPads in winter which report overheating when they have been actually freezing.