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  • Circuit board coated with black paint?

    Has anyone had the covers off of their Syncrowave welder and found black paint on the the Main Control Circuit Card? (There is no black paint on my Post-Flow and High Frequency Timer circuit card.)

    Has anyone tried to remove this black coating?

    I tried using Acetone and a Q-tip swab to remove the coating from one of the corners on the back side of the board. The Acetone did not remove any of the black coating. I am thinking of trying a regular paint stripper next.

    I suspect that the coating will have to be removed before the components on the board can be tested, and the problem solved.

    Any thoughts?

    Yours,
    Thumb Clip Pull Pin.
    Be safe. Have fun. Always do your best, and you will never loose any sleep at night!

  • #2
    1) Why are you doing this?
    2) If you are having a problem, a little more details on the specifics?
    3) They (Miller) have a reason for everything, probably to do with corporate coping, or just to keep things closer to the chest
    I would not think the board must be stripped for individual component testing, but I am not an expert on the coating.

    Comment


    • #3
      My guess is epoxy. probably put there to keep people from doing what you're trying to do! My first shot would be 1-800-4-MILLER. Free. Screw up that board = NOT free!

      Hank
      ...from the Gadget Garage
      Millermatic 210 w/3035, BWE
      Handler 210 w/DP3035
      TA185TSW
      Victor O/A "J" series, SuperRange

      Comment


      • #4
        Sometimes that was done to prevent other companies from copying the pcb technology at the time. (which happened anyway and they paid dearly for it)

        The pcb has a test panel that it's attached to at the factory that simulated all the inputs and outputs. The cpmputer will tell us what part is bad.

        A-

        Comment


        • #5
          Thanks for the replys!

          I called Miller Electric Manufacturing, 1-920-734-9821. I talked to some really nice people in Tech Service, Literature, and the Parts Department. I was told by Tech Service that Miller no longer repairs circuit boards. They told me that I should replace it or have it repaired by a circuit board repair shop. The parts department told me that the board costs seven hundred fourty six dollars and two cents to replace. The current sensor costs another three hundred fourty nine dollars to replace. Both parts are available.

          I did a google search and found ACS Industrial Services, Inc., 1-800-605-6419, in Forest Hill, Maryland. They told me to fill out one of their component repair forms and send the board to them for evaluation. I will also send in the current sensor.

          I told ACS about the black coating that is covering the components of the printed circuit board. They did not think that it would problem. (I was thinking that I would have to remove the black coating before anyone could work on the board.)

          I will clean out all of the old dust and dirt from the interior of the welder with rags and compressed air while I have these components out and all of the covers off.

          This is a really nice machine inside and out. Maybe I can figure out how to post a couple of digital pictures of it for you all to enjoy! I am really looking forward to getting the old girl running again!

          Thanks again for all of the replies! I really appreciate all of the advise and information that is shared on this web site!

          Yours,
          Thumb Clip Pull Pin.
          Be safe. Have fun. Always do your best, and you will never loose any sleep at night!

          Comment


          • #6
            I would like to see a picture of the circuit board. I reversed engineered the board in my Lincoln HF box so I could produce a schematic for trouble shooting. It is fairly easy to do depending on the parts count and if you can identify transistors and IC's. I had one IC with an oddball house number but I was able to figure out an off the shelf replacement.

            Comment


            • #7
              Thanks Mike!

              I got busy around the house last evening and did not get to make any digital pictures. I'll try again tonight after I get home from my second job!

              You must be an electronics wizard if you can reverse engineer these things. I had basic electronics many years ago in the Marine Corps.

              I have to get that current sensor out of the welder so that I can send that along with the circuit board. I am really hoping that it too is repairable at a fair price.

              Yours,
              Thumb Clip Pull Pin.
              Be safe. Have fun. Always do your best, and you will never loose any sleep at night!

              Comment


              • #8
                Pictures of the blackened circuit card.

                Here are a couple of pictures of this main circuit card for your viewing enjoyment.

                Please notice in the view of the component side of the circuit board, that capacitor C8 (in the lower left hand corner of the board) is not coated.

                Please also note that a new capacitor has been added to the back side of the circuit board and painted over. (The lower right side of the board.)

                I suspect that the board was repaired sometime in the past then sprayed over, then repaired again.

                Any thoughts?

                Yours,
                Thumb Clip Pull Pin.
                Attached Files
                Be safe. Have fun. Always do your best, and you will never loose any sleep at night!

                Comment


                • #9
                  The coating is probably a conformal coating of sorts.

                  Generally it serves two purposes:

                  1: Prevents objects from shorting out components. (dust, metal shavings etc)
                  2: Depending on certification requirements, the coating may give additional insulation for components that are closely spaced.

                  It is not a problem to take the coating off with proper solvents. Acetone will not do it.

                  If it was a security feature, chances are that it would have been thickly potted with thermal potting compound.

                  Comment


                  • #10
                    Is the coating about as thick as paint? I think I can see 4 integrated circuits on it. If the coating can be removed without taking the markings off the parts, it would not be too hard to draw a schematic. I do this by drawing the top side of the board just like it looks.

                    I then find the traces that are ground or negative. Most of the caps will have one side going to ground. I put a little mark on each component leg that goes to ground on the drawing. I then work on the other traces and draw them as they are connected. After I double check to make sure I didn't miss anything, I start drawing the schematic. It may take 3 tries to get one that is easy to follow.

                    You also have to look at each pin on the connector and see where it goes and if it is an input or an output.

                    Comment


                    • #11
                      As thick as paint.

                      Yes, that is right! The coating is only as thick as paint.

                      I down loaded a copy of Miller form # OM-350P from the Miller web site. This is a parts list starting with serial number JG064819. (My serial number is HF870XXX.) I was compairing my circuit card with the illustration of a circuit card found on page OM-350 Page 19. There seems to be a few very noticable differences.

                      Mike W.,

                      You are amaizing! I look at the card and just see components. You look a the same thing and see circuits! I like your idea about drawing the componet side of the board then drawing the "run" side of the board, then connecting the dots. I have toyed with this in the past on another project, but I never got very far!

                      I have ordered a technical manual from a local branch of National Welders. I am still waiting for it. I wish that I had ordered it directly from Miller! I am hoping to get a better idea of inputs and out puts of this board. I am hoping to understand what the circuits are supposed to do, so the problem can be correctly isolated and corrected.

                      I think that this is going to be a very nice welder. After all it has served the College of William and Mary faithfully for years and years.

                      Yours,
                      Thumb Clip Pull Pin.
                      Be safe. Have fun. Always do your best, and you will never loose any sleep at night!

                      Comment


                      • #12
                        Thumb Clip Pull, I would be glad to help you out in any way I can. I have done simple circuits in a half hour. One complicated one took me maybe 40 hours. It's kind of like climbing a mountain...why?...because it's there.

                        Comment


                        • #13
                          Hi,

                          May I ask which model of Syncrowave welder this is and how old it is?

                          When you mention parts costs of $746 + $349 = $1095 you are exceeding my level of pain for fixing old welders.

                          Does anyone know what average repair costs run on a SD180 when a problem arises?

                          TMT


                          Originally posted by Thumb Clip Pull
                          I called Miller Electric Manufacturing, 1-920-734-9821. I talked to some really nice people in Tech Service, Literature, and the Parts Department. I was told by Tech Service that Miller no longer repairs circuit boards. They told me that I should replace it or have it repaired by a circuit board repair shop. The parts department told me that the board costs seven hundred fourty six dollars and two cents to replace. The current sensor costs another three hundred fourty nine dollars to replace. Both parts are available.

                          I did a google search and found ACS Industrial Services, Inc., 1-800-605-6419, in Forest Hill, Maryland. They told me to fill out one of their component repair forms and send the board to them for evaluation. I will also send in the current sensor.

                          I told ACS about the black coating that is covering the components of the printed circuit board. They did not think that it would problem. (I was thinking that I would have to remove the black coating before anyone could work on the board.)

                          I will clean out all of the old dust and dirt from the interior of the welder with rags and compressed air while I have these components out and all of the covers off.

                          This is a really nice machine inside and out. Maybe I can figure out how to post a couple of digital pictures of it for you all to enjoy! I am really looking forward to getting the old girl running again!

                          Thanks again for all of the replies! I really appreciate all of the advise and information that is shared on this web site!

                          Yours,
                          Thumb Clip Pull Pin.

                          Comment


                          • #14
                            Sure thing!

                            Too many tools,

                            This is a Syncrowave 300. It was manufactured by Miller Electric around 1975. The machine is in excellent condition otherwise.

                            I agree that eleven hundred dollars is too much to pay to fix most old welders, but I believe that this machine can be repaired for far less than that. I have found that it is time to replace a piece of equipment once the repair cost meets or exceeds one third to one half of the replacement cost of the machine. I believe that the problems with the circuit board are simple ones. There are just obstacles such as an understanding of how the machine is supposed to function, what circuits are causing the malfunction, what components are bad. This is compounded by the lack of available information, and this black coating on the circuit board.

                            I am sorry but I don't know anything about your SD180. I would recommend purchasing every bit of information about your machine that you possible can if you intend to keep the machine for a long time. That way, you may be able to repair whatever problem may occure if and when the welder does malfunction. This information may prove to be invalulable to you in that you may be able to make a better decision as to whether or not to repair your machine.

                            Yours,
                            Thumb Clip Pull Pin
                            Be safe. Have fun. Always do your best, and you will never loose any sleep at night!

                            Comment


                            • #15
                              I agree with your comments.

                              How much is your welder worth if you could buy its equivalent working?

                              As for information about the workings of welders and the SD180 in particular, I would not hold out much hope. Miller, Lincoln and others go out of their way to keep that information to theirselves. Your coated board is an example of it.

                              One must remember that companies use their repair and parts operations as major profit centers....or in other words, the cost of a welder is not just the initial purchase price but the cost in repairs and consumables also. This affects how much you and I end up spending on every inch of weld.

                              As I have mentioned before, the introduction of inverter based machines is making this subject very interesting. In a welder like yours, at least you have a chance to repair it economically. In the newer all-in-one machines that I have looked at, a failure after the warranty ends usually means scraping the welder. I will be interested in seeing how the industry deals with this problem when the customer base starts really complaining about the cost of repairs.

                              TMT

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