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Invision 352MPA gave up on me

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  • Invision 352MPA gave up on me

    Serial MD210471U
    Bought the machine used, worked well for a few weeks and then it would spark and the weld output (blue) light would stay lit but the voltage dropped to 0, and the wire would just feed, no weld or spark.

    obtained a technical manual for the invision 350mpa which is close but not exactly what I need here. Machine is clean and beautiful on the inside, at some point someone replaced the circuit breaker on the back and left the old inside the machine, but they both check out well and the feeder seems to be working just fine (S74mpa plus dual)

    here is what I'm seeing so far on Pre power
    Section 8-5 all in spec.
    boost igbt, snubber, input SCR, input Diode all good

    Boost Snubber, ain Boost, Inverter IGBT, Snubber IGBT, Inverter gate d2 cathode all good, I dont have a D4, D10, or D8 to check

    Power sitch good

    output diodes good

    8-12 PC1 control power circuit all in spec.

    Buck IGBT u6 pin3 RC2 pin 1 reads 1.051 spec .20-.90
    don't have a D53, D60 and 61 in the same area of PC1 are ok

    All in spec except:
    Snubber gate drive IC U13 u13 pin 5 to rc9 pin 4(+15v) reads .009, spec .10-.30

    Snubber gate drive IC U13 u13 pin 7 to rc9 pin 4(+15v) reads .798, spec. .10-.30

    Boost gate protection Diode D12 reads open both ways
    no Diode D13
    Inverter gate protection diode D1 reads open both ways
    Inverter gate protection diode D2 reads 1.408 spec. .20-.90
    ​​​​​​​Inverter gate protection diode D3 reads 1.408 spec. .20-.90
    all others ok or not on my machine.

    I greatly any input or direction here. I believe the machine to be out of Warranty, is this correct? also all components I can see look to be in perfect condition. Thanks!

  • #2
    Yep she is out of warranty my question is did the unit throw an error code.


    • #3
      No error codes whatsoever, just reads 0v. when the output is on (blue light).


      • #4
        Update, it Works!!!!!!!

        Some of my earlier tests on what I thought were diodes were actually 600W translent voltage supressors, so I now believe all the primary power, igbts, etc. all ok. the machine even sounds all buzzy and healthy like it has in the past and like my Dynasty. I believe what I have here is a control side issue that may be easier to figure out with a little help.

        Recap, machine seems to be working normally and sounds healthy. when i pull the trigger on the mig gun wire comes out, blue output light comes on, but no sparks or attempts to weld, and the voltage on the machine meter drops to 0 from whatever the preset voltage was.

        Checked pin 5 on RC 6 (Output enable) should have +12.5v DC referenced to ground or pin 14, actually have 4.21v DC when the machine is at idle.
        Well, just went and retested pin 5 and got a reading of 12.5v, and the **** thing is working! Guessing a loose connection I somehow tested into compliance!

        Anyhow, thanks for the help here, if you find yourself in my spot double check all the connections! Carefully! Hopefully it lasts, I just whish I knew what I did to to make it work. I bleed Blue, and my full faith has been restored in Miller here. I am sure when the machine was not working pin 5 was reading 4.21v. any clue what would cause that? where does that 12.5v come from?


        • #5
          Everything you explained, especially the enable signal measuring low prior to turning on the output, is usually a symptom within the PC1 board. It sounds like it is working right now, but it may come back. If it does, it is the PC1 control board that has the failure. This is a known issue that has a service memo.