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Need Miller Econotwin wiring diagram

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  • Need Miller Econotwin wiring diagram

    I replaced the diodes in my Miller Econotwin HF because one was bad. I used aftermarket Chinese 200 amp diodes, 2 foreword and 2 reverse polarity. I checked them with my Fluke, all checked good. However after reassembly my output is 75 volts even when a connected to 120 volt heat lamp. I believe welding voltage should be @ 45 volts. I may have wired something wrong but the manual has only rough wiring diagram not a detailed wiring map.
    does anyone have a true wiring diagram for the Econotwin ?

    Not wanting to zap myself.

  • #2
    The Miller manual wiring diagram does not discriminate individual wires. Multiple wires are shown as one line. Eg: power lead’s 3 wires, L1, L2 and ground are shown as one line.


    • #3
      Have you looked at the schematic (circuit diagram) in the manual? It shows all the individual wire numbers and where they connect. Wiring diagrams, as you have found, are not much help. What is your serial number?


      • #4
        My manuals wiring diagram is not detailed enough bundles are shown as one line to a body component block,
        the new diodes tested OK before install.
        Miller Econotwin HF
        Model no. JB-38 can’t find a serial number


        • #5
          OCV is 75 DC and 80 AC.... A 250 watt heat lamp pulls a couple of amps.... 75 DC sounds reasonable at that load... Does it weld OK.


          • #6
            Here's the manual for your machine. Oddly, serial numbers with the two letter-two number series appears in the serial number field of the Miller manuals website page. So, this should be the correct manual for JB-38. The schematic diagram with wire numbers to show which one goes where is about 2/3 of the way through the file--you will have to pick the one that matches your welder. Should be a help. Hope you get it figured out.



            • #7
              Thanks, fixed problem. The old girl is running great again, Nice to have my favourite welder at hand.