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miller 180 mig welder gas problem

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  • miller 180 mig welder gas problem

    I have a millermatic 180 mig welder that i bought new 6 years ago. It has been a great machine until now, the shielding gas is always flowing when the welder is on. as soon as i turn on the welder you hear the click of the gas solenoid that you usually hear when you pull the trigger. If anybody knows anything about them please help me figure it out. i did try unplugging the wires to the gun and gas still flows. after that i unplugged one of the 2 wires to the gas valve/solenoid and the gas flow stopped. does this mean it is a problem in the board "hoping not" or could it still be the gas solenoid thing?

  • #2
    I replied to this same post that on welding web, so I add my reply here too.

    Probably a stuck relay on the control board. Which one I have no idea. after unplugging the supply cord from the wall outlet, you could try gently tapping on each relay on the control board with the handle end of a screw driver. If you're lucky, this will jar the stuck relay loose.


    • #3
      yeah i posted this problem on a few different forums hoping the more input the better. i tried tapping the relays with my fingers crossed but it didn't fix the the problem. if i can get help with figuring out witch relay is bad and where to buy it i can have my cousin solder it in for me. he's never messed with welders but says hes soldered enough circuit boards to be confident in doing it for me.


      • #4
        On page 42 of the manual

        there is a marginal schematic - if you look near the center of the print, you will see an item marked "GS-1", connected to pins 15 and 16 of the "vast wasteland" called "PC1 control board" - (by "wasteland", I mean they don't want you to know what's on the board, so it's just a big blank.

        I've not worked on welders much either, and no migs - but I'll lay odds that if you follow the leads from your gas solenoid on the rear panel they will end at pins 15 and 16.

        IF so, depending on how that board is constructed, you MAY be able to trace the path to either a relay, or a solid state relay of some kind. IF it's a solid state relay, it's either good or FRIED - no amount of tapping will fix that kind, only a part that is a direct replacement.

        Some manufacturers used to purposely obliterate part #'s on their boards so you HAD to go to them for the part, which (surprise) cost 5 TIMES what you could have gotten it for if you HAD the part # - but this was a long time ago - now, everything is surface mount technology (SMT) and you pretty much have to get the entire board replaced if anything goes bad.

        Hopefully, the mm180 is still discrete component construction.

        If for some reason your cousin gets stumped on this, you might take a CLEAR pic of your board, with something pointing to the two wires from the gas solenoid, and I may be able to help more. (I taught electronics in the military in the '60's, and have been in various technical fields up til I retired last year, in case you're nervous about my qualifications)

        Good luck... Steve


        • #5
          well im sorry the pictures didnt end up as clear as i hoped for but maybe this will help in figuring this out

          and the backside


          • #6
            any idea which relay it is and where to buy?


            • #7
              well my cousin works on circut boards for other electronics so he replaced both relays on the board with the exact replacement " which i had to buy 6 of them because the manufacturer has a minimum order so if anyone needs one pm me" but the problem is still there and the gas is always flowing when welder is turned on. if anybody has any ideas please help i have alot of welding projects building up.


              • #8
                Not going to be a relay in this case, likely a shorted zener on the board


                • #9
                  Originally posted by cruizer View Post
                  Not going to be a relay in this case, likely a shorted zener on the board
                  i dont know much about electronics, what is a zener? can it be replaced on the board?


                  • #10
                    Originally posted by sluginxlt View Post
                    i dont know much about electronics, what is a zener? can it be replaced on the board?

                    let Google be your friend.


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