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Millermatic 35 contactor not closing.

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  • Millermatic 35 contactor not closing.

    This machine has been upgraded to use the new style leads, which was not cheap, so not going to give up now.
    Tried to diagnose my contactor not closing all weekend. Fan runs, spool advances, gas solenoid works. Just no power to the welding wire.
    Tried to follow schematics but my machine #HF868976 does not have any circuit boards as they indicate.
    Just replaced the old pitted contactor and the new one does not pull in either.
    I did notice that the power select jumper was wrong so changed it to correct 208v but that made no difference.
    In desperation I tried jumping the contactor, then laid down the best bead of my life with C25 gas instead of the CO2 I am out of.
    So if the contactor would just close on demand the machine will outlive me.

    May have sorted this earlier today?
    New contactor solenoid is "Open" between the terminals. Vendor is replacing it, of course they are not local.
    Seems odd the new part would have the same issue as the old, but I live a charmed (Cursed!) life.
    Measured voltage at the wires and got 30v so it would seem to be plenty to energize the 24v coil windings.

    Am I missing something?
    I have pics of the inside of my machine if needed.

  • #2
    Your problem is probably with the control relay CR1 check to see if it is closing when the trigger on the gun is energized. You should be looking at the contacts with wires 2&3. Some times Tapping on the relay with the trigger pulled will probably work to let you know if the relay is bad.


    • #3
      You may have a thermostat open for the weld circuit that's not allow CR1 to close


      • #4
        The "New" new contactor may arrive today.
        I will check resistance on the coil before install.
        Hopefully this one will not read "Open".


        • #5
          Sounds like you tracked down your problem .Great job fixing it yourself and saving a bundle of money.


          • #6
            Finally got the time/necessity to put in the second replacement contactor.
            Old dog of a welder runs great again.


            • #7
              Great, glad to hear fixed it on your own you saved a lot of money.