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MM 350p trouble shooting help

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  • #16
    Now on to the troubleshooting that the Miller tech suggested: one of which was checking the PC board connection RC11 to the Display board connection JP5. I have some micro qtips and some CRC Contact Cleaner and some DeOxit Gold Contact Enhancer, so after I post this, I am going out to clean up the RC11 connector.
    Last edited by E350; 08-21-2016, 09:24 AM.


    • #17
      One more thing. Why did someone cut up and roll up and duct tape some Styrofoam cups and wedge them between the display board and the frame? What problem was that to solve? And did it solve it? Or does it relate to the existing problem? Or does it portend some problem to come?


      • #18
        Originally posted by E350 View Post
        Hey Aeronica41 what does this look like to you?
        It's a capacitor. Careful, they bite.


        • #19
          Originally posted by E350 View Post
          One more thing. Why did someone cut up and roll up and duct tape some Styrofoam cups and wedge them between the display board and the frame? What problem was that to solve? And did it solve it? Or does it relate to the existing problem? Or does it portend some problem to come?
          Now that is one fine repair method......there is obviously a crack or a bad connection of some sort in the board and someone found that a little pressure made it work, but apparently only "kinda". Not good. I would expect frustrating intermittent problems until the board is fixed or replaced. Probably sounds all too familiar to you....
          Sorry you got stuck with this.

          that fix is right up there with one I saw many years ago-opened a cabinet in a large computerized system and found a hot soldering iron-plugged in-hanging under a circuit card. Found the guy who did it-he said the card wouldn't work if it got cold.....


          • #20
            Yes, it was the "1000 VAC" written of the side of that beer canned-sized capacitor which got my attention...

            When I first turned the machine on this evening it booted as normal, but then in about 3 minutes it cycled off and was struggling to turn back on when I turned it off. Just the same problem which I reported above.

            Then I opened the cover and found what I found in the pictures.

            Then I used CRC QD Electronic Cleaner (contact cleaner) and my micro qtips were too big for the RC11 connector, so I used some of the ribbed cleaning rods in a set for cleaning carburetor passages and gently cleaned the female and male plugs. I think it was dielectric grease which had dried out which I pulled out, but I kept gently scraping and pulling crap out and spraying the contact cleaner with the little red tube dispenser into the plugs to flush the scraped debris out then let them dry a little and then sprayed a bunch of Deoxit Gold G5 contact enhancer in each of the plug ends and wiped the excess off the circuit board and plugged RC11 back together and put the machine's cover back on.

            Then I started it up. And now, it has now been a little over one hour since I turned it back on and the machine has just sat there, pretty as can be, set where I set it at 19.0 volts and 180 wire speed, holding steady not blinking not restarting, just sitting there steady. So, fingers crossed!

            It is too late this night to weld since my wife is asleep upstairs so I will have to wait until tomorrow to try to weld with it, but I think I may have fixed this issue.

            And I am leaving the Styrofoam cup repair alone, where it is...

            I am not a computer, electronics guy, or even an electrician but even I got a kick out of that guy’s soldering iron trick!

            But it wouldn't be the first time that dried out "DIE-electric" grease stopped a low voltage computer type connection. I don’t like dielectric grease. Read up on my thoughts on it here if you like:


            I hope the following moral applies to this story:

            "Mechanics look to the component. Electricians look at the wiring."


            • #21
              That us just super! Hope the cleaning does it for you. The cup may continue to compress and reduce pressure over years-keep an eye on it, and you know where to look if problems return.

              Great links on grease and Stabilant22. Thanks! I'm putting a new gas tank on my E350 today and will only put silicon grease on the non-electrical parts of the connectors. Also, the carb cleaning rods were a good idea I wouldn't have thought of. I have a pretty broad sent of dentist tools for such work. A favorite is the "spoon cleaner" they use for cleaning inside the tooth after drilling. It's like a very tiny spoon on a handle-great for reaching and cleaning.

              Heres hoping your 350p keeps humming!


              • #22
                That's clearly a factory "cup and tape" upgrade. Big money right there, especially if it's high density styrofoam and 3M duct tape. You lucky devil.


                • #23
                  Update: When my wife came down to get me it was 12:15 a.m. and the machine had been on for 2 hours and 43 minutes without a hiccup. (I was cleaning up the shop checking up on it every few minutes.) Yesterday, I turned it on, and it started at my last setting, and I welded with it without problem. So, I think we've got this problem solved! Suggestion: Do not use dielectric grease in low-voltage (i.e., computer type) connections because when it dries out, dielectric grease (which is not conductive) can actually interrupt/impede low voltage signals. Instead, use a contact enhancer such as Stabilant 22 or Deoxit Gold G5.

                  Mr. Jones: You are incorrect. This is what the Miller Tech said in response to my emailed photos:

                  "The Styrofoam cup thing is not from the factory. I would take that out as soon as possible."

                  But I think I will treat it as a factory "upgrade" as ryanjones2150 suggests and leave it alone until I can source, price and afford a new display board.

                  Big Kudos Thanks and Shout Out to the Miller Tech guys who in an email pointed me to exactly to the component which had the problem!

                  Those Miller Tech guys and gals know their stuff and are willing to help.


                  • #24
                    Bah!! What do those Miller tech guys know anyway? Clearly nothing about the proper placement of styrofoam cups or duct tape!