Power screw terminal loose from the pcb

  • Hi guys, I have a little concern about my duet wifi board.
    I noticed that the power screw terminal is not steady but it moves a bit if I touch it.
    I can feel the connectors on the pcb being a bit “loose”.
    I think it is due to the many times I screw and unscrew it reworking on the wiring on my printer.
    But my questions are:
    Is that dangerous?
    Should I replace those?
    Or could I just use the soldering iron to “re-melt” the soldering joint?

    Thank you for your help.

  • Moderator

    Can you post a few photos so we can see how bad it is?

    How old is the Duet and where was it purchased? If it's within 6 months from an authorized reseller then it may qualify for warranty replacement.

  • I purchased it from an authorized Italian retailer (compassdhmprojects.it).
    I bought it long ago so out of warranty now.
    From picture you cannot see the problem because you have to “feel” it under your fingers.
    The appearance is perfect, just this little “gap” when you try to move the green terminal.
    As I told, It is due to excess torque in screwing the terminal multiple times, not to a fabrication defect, so entirely my fault.
    Just wandering if I could run this way or do something.

  • @lucagirolamo said in Power screw terminal loose from the pcb:

    Is that dangerous?
    Should I replace those?
    Or could I just use the soldering iron to “re-melt” the soldering joint?

    as its not under warranty then, yes its "dangerous" it causes high resistance and localized heating that can cause terminal to melt.

    you don't need to replace the terminal if it is still nice and shiny on the metal parts, if it looks burnt then I'd replace it.

    add some flux and reflow the solder joint will work, but it will be tricky without a powerful iron and pre heating the board as there is a lot of copper to heat.

  • Ok, I have a Hakko FX-888D that I never really used, I think this is the right time to do so 🙂
    Thank you all for your help

  • Just be ware that if you apply too much heat the copper trace can delaminate from the board this is why I recommend pre-heating the board to 100-120C, makes much less of a temperature difference to make up with the iron.

    Also the flux is quite important to make the old solder flow and remove oxidation and other contaminants.

  • I cannot preheat the board since I have not the right tools. But I can regulate the soldering iron temperature. What temperature do you suggest is good to do this task? 350 C maybe?


  • Hard to say, I'm not familar with Hakko and it also depends on the size of the tip, type of solder etc, but probably in that ball park, hopefully a little less will suffice.

    In general you want the biggest tip practical, and high enough temperature to finish the joint in only a few seconds. Wet the tip with a little bit of fresh solder to help with heat transfer.

  • Thanks again. I will try.

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