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Bed Thermistor constantly reading 23-25C...  

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sungod3k
(@sungod3k)
Active Member
Bed Thermistor constantly reading 23-25C...

Hi, 

im having some issues with my MK2S. im getting the "bed preheat error", so i checked the thermistor. I connected to pronterface and im getting a "normal" reading of 23C from the bed thermistor. 

When I heat the bed, im getting the temp goes up 1-2 C (could also be random fluctuations) and then I get the thermal runanway error. 

When I blow-dry the thermistor or just take it between my hands the temp doesnt go up as well. It maxes out at 25C. 

I took a spare thermistor i had laying around but it behaves the same. 

 

Im really puzzled by this. There is a signal that looks realistic but it doesnt react to any temp changes. What could be?

 

Cheers F.

 

 

Posted : 23/06/2023 5:10 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE:

Prusa Knowledge Base might help:

https://help.prusa3d.com/article/preheat-error-heatbed_2161

https://help.prusa3d.com/article/multimeter-usage_2117

Heatbed resistance on MK2 printer should be about 1 Ohm.

good luck!

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.

Posted : 23/06/2023 9:21 pm
sungod3k
(@sungod3k)
Active Member
Topic starter answered:
RE: Bed Thermistor constantly reading 23-25C...

Yeah i consulted those articles, but they dont quite describe the issue im having. Im getting a signal but its not moving the temp correctly. 

Ive never seen it like that. Either the thermistor is broken and doesnt give a signal or something like constantly -15C or it working normally, but showing that normal room temp range but not moving above it is weird.

 

 

Posted : 23/06/2023 10:50 pm
karl-herbert
(@karl-herbert)
Illustrious Member
RE: Bed Thermistor constantly reading 23-25C...

Try to heat the thermistor with a hair dryer. If the temperature display on the LCD does not increase significantly, there is a fault with the thermistor, connectors, leads or the printer board.

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.

Posted : 24/06/2023 12:56 am
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