print stopping with error message "mintemp triggered"

mitch25

Hi,
everytime I start a print, after a few hours (almost always after the same amount of time) the print is halted because it says the extruder has triggered the mintemp. The other weird thing happening, is that sometimes, the extruder temperature drops, and shows in the log two lone "cold extrusion prevented" both registered at the exact same time, and then its back to normal again. But right before i get the message that the mintemp has been triggered by the extruder, there are a series of "cold extrusion prevented" until it shuts down.
I've changed the thermistor and it still happens, so would anyone have any further insight on this? is my heater cartridge bad?

Repetier

Most likely a wire to thermistor is broken/bad contact. Works most of the time but sometimes it has no contact somewhere causing temperature drop to min temp which causes cold extrusion prevented and the error message. So best is to replace the thermistor with wires with a new one.

mitch25

But the weird part is that the temperature starts dropping, and when it does, there should be an error message saying: "Heating Failed" because RAMPS is supplying current to the extruder, but the extruder is not heating. What could the reason be?

Repetier

You wrote yourself: print stopping with error message "mintemp triggered"
That means there is no reading at all, not even room temperature. So that would not depend on getting no power. It is more the other way around. Because of this error firmware disables heaters and then it gets colder and doe snot heat any more. For this a short interruption of the cable is enough. Have heard about printers where the pressure on the sensor was big enough to make them fail after a while when being hot. Might as well be your problem. So in any case if you get the mintemp triggered regularly switch the thermistor and try again.