Miller legend nt help

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  • Motorboard
    Junior Member
    • May 2016
    • 2

    Miller legend nt help

    I have a legend nt I bought a few years ago don't do a lot of welding but I do use it for z generator on job site recently it started jumping back and forth from idle speed to weld speed and won't idle lock ser# kh368328 any help would be greatly appreciated
  • cruizer
    Senior Member
    • Oct 2004
    • 8681

    #2
    Going to guess and say you have a frazzled (stuck) CR3 relay. You serial# is incorrect

    Comment

    • duaneb55
      Senior Member
      • Aug 2008
      • 1571

      #3
      What's wrong with Motorboard's unit SN Jeff?

      AEAD Legend, The Legend, Miller Legend NT. Similar names for different machines. It's almost like Miller tried to make things confusing.

      But his posted SN comes up as Operator's Manual OM413 for the Miller Legend NT and CR3 in that machine simply by-passes the fine voltage rheostat at low idle/power speed.

      As such, I'd suspect a faulty idler module for incorrectly energizing throttle solenoid control CR1 seeing as the machine is still acting up with the idle lock on which takes CT1 out of the equation as you know. This is presuming RUN/IDLE is selected on the ignition switch.

      Slight chance it could be a bad CR1 making contact from engine vibration and that would be easy enough to check by testing for 12VDC between idler module terminals C & E when it goes to high idle/weld speed. If the switch settings are such that it should stay at low idle/power speed and idler module terminals C & E have 12VDC across them, it's an indication to me of a defective module.
      MM200 w/spot controller and Spoolmatic 1
      Syncrowave 180 SD
      Bobcat 225G Plus LPG/NG w/14-pin*
      *Homemade Suitcase Wire Feeder
      *HF-251D-1
      *WC-1S & Spoolmatic 1
      PakMaster 100XL
      Marquette "Star Jet" 21-110
      http://www.millerwelds.com/images/sm...rolleyes.png?2

      Comment

      • cruizer
        Senior Member
        • Oct 2004
        • 8681

        #4
        Cause the Ledgend NT didnt start being built till KH369... least wise, thats what the technical site says. . So the 8 may be a 9.... Cause the idle speed is jumping and doent lock, its likely not CR1, so CR3 popped up. weak idle solinoid maybe., but I dont think it has a separate hold and pull function. just pull and hold. 75 % of the time is a corroded junction block on the firewall, between the engine and generator.

        Comment

        • duaneb55
          Senior Member
          • Aug 2008
          • 1571

          #5
          I see something different with KH368328 but that's beside the point.

          Idler module energizes CR1 to pull in throttle solenoid TS1 to take engine to high idle/weld speed not the other way around. The Legends are the odd balls in that regard and I agree it's not very likely at all that CR1 is bad. I can also say it's not CR3 as well.

          Are you looking at schematic drawing 184 759-A?

          Last edited by duaneb55; 06-07-2016, 08:19 PM.
          MM200 w/spot controller and Spoolmatic 1
          Syncrowave 180 SD
          Bobcat 225G Plus LPG/NG w/14-pin*
          *Homemade Suitcase Wire Feeder
          *HF-251D-1
          *WC-1S & Spoolmatic 1
          PakMaster 100XL
          Marquette "Star Jet" 21-110
          http://www.millerwelds.com/images/sm...rolleyes.png?2

          Comment

          • Motorboard
            Junior Member
            • May 2016
            • 2

            #6
            Thank you for your help I'm currently recovering from a car wreck I'll get some help in a few days to help me check it out and post results. Your help is greatly apprecited. The ser# is what's on machine I'll double check it

            Comment

            • duaneb55
              Senior Member
              • Aug 2008
              • 1571

              #7
              So sorry to hear of your misfortune. Wishing you a full and speedy recovery.
              MM200 w/spot controller and Spoolmatic 1
              Syncrowave 180 SD
              Bobcat 225G Plus LPG/NG w/14-pin*
              *Homemade Suitcase Wire Feeder
              *HF-251D-1
              *WC-1S & Spoolmatic 1
              PakMaster 100XL
              Marquette "Star Jet" 21-110
              http://www.millerwelds.com/images/sm...rolleyes.png?2

              Comment

              • hagball52
                Junior Member
                • Jan 2020
                • 1

                #8
                I have recently acquired a Miller Legend NT. It looks like the generator has been replaced at some point because all of the white wires coming out of the generator have been butt spliced going to the control panel and auxillary power outlet. The problem I'm having is it won't idle up when I strike an arc to weld. It will idle up when I turn the idle/run switch to run and it will idle up when I plug a grinder into the auxillary power outlet and turn it on. I've checked the wiring diagram and it shows two wires going to transformer CT1 (# 91 & # 71) and the two wires (#8 & #33) going to PC1 the idle/run control unit. My welder has no #71 wire. I have searched all over the unit for that wire. One end of it comes from the weld winding and goes through the transformer CT1 and attaches to terminal #75 @ S4. I'm not sure what S4 is or where it is and I'm starting to think that the generator that is on my unit does not have wire #71. It welds fine when I turn it to run on switch. If someone has a picture or can tell me about that #71 wire going to transformer CT! it would be greatly appreciated. My welder serial number is KJ292993. I will buy you dinner and a cocktail if anyone can help.
                My wiring diagram is on page 29 OM-413
                Last edited by hagball52; 01-20-2020, 06:57 PM.

                Comment

                • welderman2020
                  Junior Member
                  • Jul 2021
                  • 7

                  #9
                  Number 71 is a transformer wire going into the voltage regulator according to my diagram

                  Comment

                  • welderman2020
                    Junior Member
                    • Jul 2021
                    • 7

                    #10
                    It's a green wire coming off the plug to the PC card

                    Comment

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