Jumpy Hot End Temperature

[toddtman]

Hey All,

I recently noticed that the temperature on my hot end will jump around a lot. It happens while printing,heating, and cooling. Sometimes the temperature graph is smooth but other times it will jump up or down by up to 25 degrees. I checked all of the connections and they seem to be secure. Any ideas? Attached is a screen clipping of the simplify 3d graph.

Thanks in advance.

[ednisley]

they seem to be secure

There's a wire in the process of breaking, most likely at the thermistor itself, that's presenting an intermittent high resistance = low temperature to the circuitry in the RAMBo.

The solution, after trying all the other things, will be to replace the thermistor.

More info in this recent thread:
viewtopic.php?f=7&t=2630

[toddtman]

I broke out the old dmm and testing the resistance of the thermistor again but this time wiggled the wire. With that, the resistance value skyrocketed. I will just have to order a replacement. Thanks for your help @ednisley

[ednisley]

but this time wiggled the wire.

Once you know where to look, it's easy to find! [grin]

We really need a sticky note explaining what to do when the temperature readouts get twitchy, because it happens a lot...