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Help Needed Miller 330A/BP TIG welder

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  • Help Needed Miller 330A/BP TIG welder

    I bought this used a few years ago. It's a real beast, all 830 pounds of it. It works fine, except I cannot switch over to standard welding mode. I have some low clearance overhead welding to do, while on my back, and cannot use the remote pedal. The remote works fine, but when I switch over to standard mode, nothing. Both toggle switches are over to standard, nothing. Is there something I am missing to do? I was told it was originally an airframe welder, for an aircraft company, that the last owner had worked for. He is now deceased, so I cannot ask him. Maybe it was specifically modified for the aircraft company, that's out of business too? Any info on this would be appreciated.

  • #2
    Need a serial number to find the right data.

    May have been modified, or maybe just a switch or wiring problem. Are you able to safely dig into live equipment with a voltmeter? Knowledge of electrical safety inside equipment? Don't want to see you get hurt trying to fix this.
    Last edited by Aeronca41; 03-01-2020, 07:44 PM.


    • #3
      The serial # is K192233. I do have a voltmeter. As long as I would know where to probe I am ok with doing it.


      • #4
        Are you trying to stick weld or scratch start tig?


        • #5
          Originally posted by ryanjones2150 View Post
          Are you trying to stick weld or scratch start tig?
          That's a very relevant question. I just assumed scratch start TIG but that may be wrong.


          • #6
            Originally posted by GBertolet View Post
            The serial # is K192233. I do have a voltmeter. As long as I would know where to probe I am ok with doing it.
            That's good. Will try to help you through it.

            It appears you are missing a letter from the beginning of the serial number. Every manual I see starts with the usual two-letter prefix. There is always a catch-all entry in the Miller SN list that goes to ZZZZZ, so I tried that one, but that takes me to a manual that doesn't have the usual "STANDARD" label on the switches--it's the last manual, for last serial numbers they made. Instead of, for example, the usual Standard/Remote, they label the switch "REMOTE" and then show on/off. Since you mentioned the "standard" position, I assume you have one of the older units and the serial number must be wrong, or someone has replaced the front panel.


            • #7
              I wanted to scratch start TIG.


              • #8
                OK--assumed correctly. Check on the serial number.


                • #9
                  This sounds dumb, but I can't find the serial number on the welder. It's been years since I wrote the number down. I don't remember where I got it from. The welder has some light surface rust, and is back in a corner. Where should I look?


                  • #10
                    They put them various places over the years. Sometimes on the top left of the front panel, stamped into the faceplate. Sometimes a separate metal plate to the left of the polarity selector switch. Maybe lower center or lower right of the faceplate--I think I may have seen a picture or two with the number down there. I think there were even some that had them down by where the water cooler lines come out, maybe on the vertical side of the cabinet in the little recess there. Would be nice if they were always in the same place, but I know they weren't. You have to wonder why they thought it was a good idea to keep moving it around.

                    Example of upper left:
                    Click image for larger version

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                    Example of the metal plate on the front panel--left center.
                    Click image for larger version

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                    Last edited by Aeronca41; 03-02-2020, 12:36 PM. Reason: add photos


                    • #11
                      Here are some photo's. I did find the serial number. It was right under my nose.
                      Attached Files


                      • #12
                        Strange serial number. I'm going to send your photo to Miller Tech Support and see if they can identify the correct manual.

                        Tell me about looking for serial numbers. I was looking for it on my Trailblazer 280NT and ended up calling Miller to ask where to find it. Guy said,
                        "Man, it's right on the front panel". Looked again, and sure enough. Made me feel like the village idiot.


                        • #13
                          Remote amperage control switch to standard.
                          Contractor control switch to standard.
                          HF switch to off.

                          Lift the hood....

                          Start circuit switch to off.
                          Swing the big lever from TIG to metallic.

                          See if she chooches.

                          If no choochy, try unplugging the foot pedal cables. I’ve never tried that, but one of my other machines has to have the foot pedal unplugged in order for it to operate in the standard mode.

                          Try to stick weld with her too.

                          You’ll also have to have a valve torch since the contactor won’t be operational.

                          I’ve scratch start tigged with mine tons of times.


                          • #15
                            My welder does not have a start circuit switch, or a lever for TIG to metallic. It is a bus bar instead. This welder really must be old. And I will check the toggle switches for remote/standard, IMG_0522.JPGClick image for larger version

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                            Last edited by GBertolet; 03-03-2020, 02:15 PM.