Unreliable temperature for 1st Extruder (on I3 pro C dual)

[maesa]

Hello,

I bought a "Geeetech Unassembled Prusa I3 pro C dual extruder 3D printer DIY" in July this year.

For the last weeks, I am experiencing issues with the temperature sensor of the 1st extruder. While printing with a target temperature of 230°C, the value of the head temperature quickly jumps to erratic temperatures between 160 and 260 °C - see screen capture of the temperature curve in Repetier.

Obviously, the "real" head temperature corresponds to the maximal reached temperature, but as it sometimes "feels" colder, the head warms up and it overheats up to 260°C... Conversely, it happens that it feels so cold that the extrusion pauses due to "cold extrusion protection" although the printer continues his movements. Of course, this leads to failed prints...
It also happened that I got an "Err Min Temp" message (temperature = 0) but only during a few seconds or minutes.

The second head is working fine - temperature is changing very smoothly, as expected.

I believe that this is an issue with the temperature sensor itself - everything else is working well (board, steppers, extruder, etc.)

How may I solve such an issue ?

Yours,

A. Maes

[maesa]

Hum... One week later and still no reply from Support, not even to the Technical Support Message I left using the Contact Form. What else should I do to get help ?

[William]

I guess you may have a similar problem in this post:
http://www.geeetech.com/forum/viewtopic ... 459#p33459

[maesa]

Indeed. It is exactly the same issue. I'll try to fix it the same way. Thanks.