Z motors messed up



  • My Z motors are having some kind of issue. I left a print running last night and this morning the z axis would only run in one direction. I have 2 z motors and one of the z motors cables has a burned spot on the connector for the red and blue pin where it connects to the board (z1). Both z1 and z2 are having the same issue.

    Previously I have had a issue with the fan VIN not working correctly I switched it to the 5 volt and it has bee working fine. I purchased the unit in January and have not had any other issues with it.

    Any guidance ?


  • administrators

    Most likely there is a bad crimp connection on the connector pin where that burned spot is.

    The fan not working when the fan voltage selector jumper is set to VIN probably means that you shorted out one of the fan connectors and fused the trace between the + side of the VIN terminal block and the VIN pin on the voltage selection jumper. You can bypass that trace with a wire on the back of the board.



  • You can see the burn mark here the crimps on the end looked good.

    https://www.dropbox.com/s/txm4dqul1nnpmuf/IMG_0728.JPG?dl=0

    Do you think If re-crimp the ends it will be ok?


  • administrators

    The burn mark indicates that one of two things happened:

    1. You had a bad connection on that pin. It was probably a bad crimp connection, but possibly the crimp pin was distorted so that the spring didn't make good contact with the pin. Also check that the soldering of those two pins on the underside of the Duet is sound.

    2. You had massive overcurrent on those pins, most likely because of a short between those two wires. If so then there will probably be a burn mark on the stepper driver too.

    The fact that both pins were affected suggests over-current.



  • No burn marks on the underside or around the stepper. I rewired it but now its not driving the motor at all. ( I also checked the motors on the other x and Y ) It has been working fine for about a month. Any other Ideas?

    Thanks
    Eric


  • administrators

    What do you mean by "I also checked the motors on the other x and Y" ?



  • I verified that the motors work by using the x and y connectors.


  • administrators

    If you are sure that the wiring was OK then I suggest you make a warranty claim. See https://www.duet3d.com/warranty.



  • Ok thanks I will recheck everything again tonight.



  • Ok – so the same issues happened again. the z-motors are messed up after a print (4 hours ) and one of the motors has a burnt pin. ( this is with the same motors but a different duet wifi). I am beginning to believe its me and not the duet. I had not touched anything on the duet and it has been printing fine for a couple of weeks. I guess it could have been a bad crimp but I don't really believe it. What else could cause the over current?

    I will re-crimp the wires and see if the driver is ok.

    Thanks
    Eric Smith


  • administrators

    A burned pin normally means a bad connection between the wire and the crimp or terminal block etc.



  • Checked that , is there something on the motor itself that could cause this. The board has been installed for a couple of weeks now. This is the second time this has happened to me with 2 different duets. I see at least one other thread on the same topic.


  • administrators

    If you mean a burned pin on the connector on the motor itself, then it could be a bad connection inside the motor. But it's more likely a bad crimp connection in the wire going into the connector.

    If you mean a burned pin on the motor connector on the Duet, then it'a almost certainly a bad crimp connection on that pin. But check the underside of the Duet too to make sure that the pin is properly soldered into the PCB.


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