If you're getting dodgy readings when the bed is cold then I think a sensor replacement is in order.
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If you're getting dodgy readings when the bed is cold then I think a sensor replacement is in order.
Just reporting: I replaced the thermistor on the heated bed, my temperature reading is now much more accurate and within the expected 5%.
I used this one: Cantherm MF58104F3950, got mine from ebay but digikey should have them too.
Digi-Key Part Number 317-1380-ND
Resistance in Ohms @ 25°C 100k
B25/50 3950K
Operating Temperature -55°C ~ 200°C
Mounting Type Through Hole
Package / Case Bead, Glass
The original was at 64kOhm while the new one was at 110kOhm. I took the readings on the fly, that's far away from a trustworthy measurement - but shows for me that the original one is clearly the wrong part.
If it helps anyone, I wrote up what I did to mine, and why, at http://www.thingiverse.com/thing:1403267
Awesome.. thanks for letting us know.. I'll get ordering a thermistor and replacing mine..
I wonder why they did that.. Hard to believe it's an oversight.. I wonder if it was an easy way to ensure no one was having the bed too hot?