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Tigweld AC-DC pedal not working need expert help

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  • Tigweld AC-DC pedal not working need expert help

    I have a Tigweld AC-DC OM-771 Spec#408877-1 and I am unable to control the amperage with the pedal. It starts the machine and arc but does not control the amperage. When I press the peddle, the arc starts at what ever amperage is set by the control knob on the front panel. Does anyone have a pin out of the 10 pin foot pedal wiring so I can start to try and diagnose the issue? Or has anyone had this problem before and can help me find the problem? Please help, the welder is basically useless like this.

  • #2
    A and B are the switch for the contactor on/off control, D is reference from amp control on the machine, E is the wiper of the remote pot and F is control common.



    • #3
      Thank you Keith. Sadly the pedal is working correctly. Can you provide any other suggestions? Possible identify which circuit board is the one that is used for remote amp control? Can they be tested or do I just need to replace it? Can they be found anymore?


      • #4
        Was this ever figured out?
        I have the same machine and same problem.
        All the way up into the control board inside the welder all three wires from the pedals pot are all correct.

        Keith, do you have the manual for this?
        Also I have the amplifier chip and opto couplers coming to me, what are the odds one of those items failed?
        Is it more likely that one of those failed or one of the many diodes resistors or capacitors has caused TT issue?
        I have h11c1 h11c6 and mc3404L on the way to me, the only one I have not got coming my way was the mounted to-99 package 8 pin lf356.
        Any info from either of you?


        • #5
          Hopefully my notes added to the photos show up