X Axis jumps randomly during printing



  • While homing during the start of a print the X stepper made the damnedest noises. I go over to the computer and I see a long list of X stepper short detected messages. Then I restart the print and it works fine for the first 4 layers. Then I hear it making a new noise and it starts jumping in the wrong directions losing its place. I of course verified that there was no physical blocks. Your guidance will be greatly appreciated.

    The printer is a sidewinder X1, with an E3D hemera, bltouch, and of course a Duet wifi 2.

    The printer uses a breakout board on the X axis. Upon inspection the female connectors are 90 degree connectors and have exposed metal on the back side. The endstop runs 5V power and has a signal pin.

    Let me guess, this means that the 24V stepper power likely got shorted to the 5V rail killing the processor? If this is the case, I have an SMD rework station, is it possible to replace the processor?


  • Moderator

    @Sphyloid said in X Axis jumps randomly during printing:

    The printer uses a breakout board on the X axis. Upon inspection the female connectors are 90 degree connectors and have exposed metal on the back side. The endstop runs 5V power and has a signal pin.

    Can you post a photo? I'm not sure how you'er jumping to 24v shorted to 5v and a dead CPU. Does the Duet still respond?



  • @Sphyloid said in X Axis jumps randomly during printing:

    Let me guess, this means that the 24V stepper power likely got shorted to the 5V rail killing the processor? If this is the case, I have an SMD rework station, is it possible to replace the processor?

    Thats a bit of a leap as suggested above; the stepper drivers doesn't output 24V, they're current controlled and due to the low impedance of the most motors the voltage can be as low as 3-5v for a nominal current. There is also input protection on recent Duet2 boards that should survive 24v.

    https://duet3d.dozuki.com/Wiki/What_to_do_if_your_Duet_won't_respond might help you evaluate if you're having problems connecting to the board after the incident.

    To answer the question, yes, its possible to replace the processor and the replacement will already have the bootloader allowing you to flash the firmware using the firmware fallback procedure after the replacement. But identify the fault first, then start ordering parts.



  • @Phaedrux The Duet still turns on and runs fine until it skips X around. I found where the short was and all it had access to short was the X endstop and X stepper.

    Ended up ordering a replacement, had to go with a cloned version since I could not find a real duet anywhere. The printer works fine now. Though I found there was no cooling for the duet, the rear of the board had little to no clearance and the board cooling fan was choked with the air flowing away from the board instead of under.

    I added hotglue to the main ribbon solder joints and the rear of the connectors and removed the grounding wire that may have shorted them. Also I wired the X stepper directly to the board so that the breakout only has the 5V endstop.

    Thank you for the help guys, looking forward to having my duet running on another of my machines.

    X_Board_A_1024x1024.jpg


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