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syncrowave 351

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  • syncrowave 351

    I have searched for syncrowave 351 will NOT stick weld, but have only found tig welding problems. Started several years ago problem would only last a few seconds. I would always assume it was an improper ground. As the time increased noticed it was not a grounding problem, and noticed I would not have any indicated voltage . As I said it would only last for a short period of time. I would let the machine run for a minute or so and would watch the volt meter on the panel and wait to see it read voltage.
    The machine would then stick weld with no issues.
    I have owned the machine since it was new in 1995, I have kept it clean and adjusted. I am the only user. Problem has progressed to the point it will not stick weld at all.
    It still functions in tig mode.
    I have pulled the access panels attempting to find something obviously wrong, I see nothing burned or discolored.
    Thank you.

  • #2
    Will need your serial number.


    • #3
      stock number 903219-03-01


      • #4
        I'm not a welder tech, just an old systems engineer who has fixed a lot of stuff over almost 60 years. Since all the smarts of this machine are in circuit boards and there is no data available to see what goes on in there, I'm guessing you are either going to need a new PC1 Main Board or help from someone who has enough electronics engineering knowledge to reverse-engineer a schematic diagram from the board and try to find the bad component--a very long and arduous process. However, don't go out and buy a board based on my input. One of the Miller techs may respond to this thread, or you could just try calling Miller tech support. They are generally very helpful in leading you through diagnosing a problem.

        One thing I would absolutely do before spending any money is UNPLUG, then look inside the machine for some foreign object lying around the board or wiring where wires 60 and 61 connect to terminals RC3 and RC4 on the board. My reasoning is this: the MODE switch on the front panel connects those two pins on the board together when you select TIG. They are disconnected from each other when you select SMAW. So, the board "knows" to do stick by those pins being disconnected. The fact this was so intermittent for so many years could be due to some flux on the board that didn't get cleaned properly at build time, making a flaky high-resistance connection, a piece of wire or other conductive metal floating around, or whatever. Also look at the switch and be sure it's not making contact when it shouldn't. Any one of those things could be causing the board to not be able to figure out if it's supposed to be doing stick or not. All of this seems like a long shot, there is probably a bad part on the board, but I would look around those pins with a good light and magnifying glass. I don't know if you can see both sides of the board or not; that may be difficult based on how it's mounted. I have fixed a lot of things over the years by just "lookin' and pokin'" (very carefully) and finding something obvious. My gut says you probably have a bad component on the board, but I always do the cheap stuff first! Again, don't go out and buy a board without some confirmation from a real expert.

        I tried looking up that board (154919) at to see how much it costs, and got no hits, probably because it's so old. However, Miller often updates part numbers. If you call them, ask for a current part number for that board, just so you know.


        • #5
          Thank you Aeronca41, I will take a second look at the items you mentioned. I should have increased my search options as I actually did find another thread on a syncrowave 250 with the same problem.
          I have tried Miller tech a year or so ago, did not have much luck. The machine would always resume working, left it on last time for about 45 minutes whilst finishing up other priorities until heard the familiar click that signals voltage has returned.
          Don't weld as much as I use too, but I do need it. If all else fails I will take it to a service center in Merced that was recommended to me during said conversation with that Miller tech rep .
          Thank you again.


          • #6
            Glad to try and help, but can't do much with everything on a board into which there is no insight. Good luck.

            Merced! Brings back memories of another life long ago -- had forgotten about it--when I used to drive from Sunnyvale, down 101 to Gilroy, sniff the garlic in the air, and head over the Pacheco Pass on the way to Castle AFB. Did some work with B-52/KC-135 simulators there. Nice country.


            • #7
              When Sunnyvale and the rest of the bay area was nothing but orchards, beautiful place. Worked at Moffett field on P-3s. Castle air force base has a very motivated membership that has made a very nice museum. They recently put a Douglas A-3 ( B-66 for the air force people) I worked on A-3s going back a few decades VQ-1 on Guam.
              About my welder,, I am currently putting together a three point hitch for my Masset ferguson 175, tired of working the screw jack on the 505 baler. I have gone thru the measuring, cutting grinding and all that, just a few details remaining.
              I will then push the button, if nothing happens I will turn the power off un wire from the panel and start in on it.
              Wanted to thank you again. I will hopefully find something noteworthy and proceed ahead.


              • #8
                I spent a couple of summers at Moffett working simulators for P-3C in the big blimp hanger. Lived in an efficiency apt. at the Sundial Motel on El Camino; I think it was in Mountain View. I still remember those fresh nectarines! Can't buy anything like them here in NY. The outdoor museum at Castle was nice even decades ago...doubt I'll ever get back to CA, but if I do, I'll definitely have to go take a look there just for old times sake. That was the first place I ever saw a B-23 and a Vulcan. Remember it well. Just took a look at their web site. Brought back more memories. I have a good deal of time boring holes in the sky looking for lost people over the Atlantic in C-130s and HU-16s in the Coast Guard. Did avionics and flew as radio/nav guy.

                I remember the B-66/A-3. Quite a step up from the old A-26!

                I sure do get the benefits of the three point hitch! Removes a lot of labor, and I'm all about removing labor these days! Best of luck with the welder. Wish I was closer to try and help out.