dnaba559

Found the issue. Arduino was the problem. Even though I could not find any mechanical damage on the arduino board, it somehow caused the jumpy temperature reading and it prevented the UM from printing when it hit the target temperature. Since the arduino is not soldered onto the electronics, it can be easily replaced. Thanks for the support - hope someone will read this if he has a similar problem. rgds D

The same happened to me. My Arduino survived, but had to replace two stepper drivers. To check wheter those still work, you would however need a working arduino (or similar from ebay or amazon). You can then use a simple pinboard, some jumper wires, a 12v battery and some lines of code to see if your stepper drivers survived. You would have to upload the code to the board to turn the stepper motor via the stepper driver. Watch some youtube videos on "polulu a4988 bipolar stepper driver with arduiono" if you like.

Hi gr5, Thanks for the tip. I've set the temperature to 0 and tried a print - and there it was! The printing movement started. However, as soon as I set the temperature above 0, e.g. to 20 degrees, the printing process does not start after reaching the target temperature. I have checked the wiring of the cartridge, looks absolutely fine. The temperature curve still looks random and erratic when heating up and still randomly fluctuates around the target temperature with ca. +/-5 degrees. Regarding the Marlin firmware: I did not play with the PID values. I have simply upgraded the firmware via Cura. I also tried to print via Pronterface - with the same disappointing result. As the printer movement appears with 0 degree target temp, but does not appear with any temperature higher than 0, it seems to me as if signal to start the print movement when target temperature is reached, is not send or not received properly somewhere whithin the system. Does someone has any ideas about the cause of such an error? Thanks in advance, Rgds D

Hi Ian, Thanks for your response. I will check with a new heating cartridge and then check the soldering. I have now also checked with a marlin firmware and pronterface, but the same issue keeps showing up: heating up with a volatile temperature of -/+ 5 degree fluctuation to the target temp, where it remains but no printing movements occur ...so software or firmware errors can be excluded i guess... I will post some pics of the electronics. Any help much appreciated! Rgds D

Dear all, I have an issue which I've been trying to resolve for ages. I've replaced almost every part trying to troubleshoot this one, but no luck so far. The problem is, that my UM1 heats up, but the temperature curve is pretty jumpy (not as smooth as it used to be in the early days). When it reaches the target temperature it fluctuates around it but the printing process doesn't start. I've tried homing and jogging, both works fine. I tested each stepper driver outside of UM, all of them work fine. I've replaced the thermocouple amplifier unit. I've tried the old Cura. Even bought a new heater and thermocouple (will test it today). But I somehow het the feeling that the problem is with the electronics. I'm really close of throwing the whole thing out of the window, so if you have any hints, please let me know :-P regards, D