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Trailblazer 251 circuit board

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  • Trailblazer 251 circuit board

    Hey guys I'm new to the site and I'm looking for some help. I have the opportunity to pick up a Miller Trailblazer 251 pretty cheap and the issue is the circuit board is burnt up in it. The only problem is I called and apparently miller doesn't make it anymore. So I sent that board off only to find out hat it couldn't be repaired. So I wanted to see if anyone knew where I could get my hands on one or if someone had one laying around in a parts machine. The number on the board is 198412b. Thanks in advance.


  • #2
    Miller4less will sell you one for a steal at $2,437! ... I bet they're just flying off the shelves at that price...

    Unless it's a crispy blob of epoxy potting, I don't buy that it can't be repaired. Try a better shop.

    Forum member Cruizer probably would be the one most likely to have a pile of parts, but he hasn't been on much lately - you might try messaging him if he doesn't spot this thread.


    • #3
      Can you post pictures of both sides of the board, just to see how bad it looks?


      • #4
        Sorry guys i haven't been around a computer and my phone wouldn't let me sign in to the page. Bushytails thanks for the info. Aeronca41 I will post pics as soon as I get it back from the repair shop. They are shipping it back to me.


        • #5
          Sorry it took me so long but here are pictures of my circuit board.


          • #6
            Oooohh--that's ugly! But, I have to agree with Bushytails--if you find the right guy, it think it can be repaired. I would definitely fix it if it were mine; I've repaired worse. Biggest problem is you are going to have to find a schematic for the board, in the Tech Manual, which may be difficult. Need the correct serial number range. Might find one on ebay. My problem is I can find sometimes find the manuals, but they're for the wrong serial number.

            Biggest problem with fixing it is if you go to a welder repair shop, the labor to repair it (in the rare event they have someone capable--not likely) is probably going to lead you back to that replacement cost. Know anyone with engineering as well as circuit board repair skills who does this stuff as a hobby? I would suspect that is going to be your only cost-effective solution.

            I have been saying for over a year that I'm going to get my test bench re-estabished, but that's looking more and more like winter--was supposed to be last winter.


            • #7
              Yeah, that's close to being a crispy blob. But not quite!

              I'd want to do a bit of determining why it failed in that fashion before repairing it, and a check for how much collateral damage there was. For example, did it vaporize because the 240V winding is shorted to the exciter winding? That's a pretty impressive amount of arc damage for just the exciter voltage, and I would have expected the bridge rectifier to short before then.

              If, and only if, the failure is not due to a catastrophic failure elsewhere in the machine, my repair strategy would probably be to repair the driver on the board (you can be fairly confident whatever was hooked up to that transistor is toast too, then keep following the bad parts back until you hopefully don't get to anything with programming), but mount the new transistors (chances are more than one is toasted) off-board on a random heatsink (probably needs to be isolated), with wires to appropriate places.

              As to the implied question... unless "pretty cheap" means "bring a trailer and a six-pack", you might want to keep looking...


              • #8
                Okay thanks for the input guys. I did find the capacitor that was attached to it with the side blown out of it which I got a new one of them. I don't know if that would help with diagnosing anything. Do you guys have any recommendations on someone that might want to take a stab at fixing it or too be honest I was hoping someone would see this that had a parts machine with a good circuit board. One can only dream. It might also just be a lost cause. Anyway thanks for all of the help.


                • #9
                  Well, the side blown out of a capacitor means one of three things, kind of a restatement of what Bushytails alread said.

                  --The cap died of old age--shorted internally and blew up. No other cause than just old age. Not real common, but it happens--I've seen it a number of times, but its more likely that:

                  --Something happened (some pother component failure) to cause the cap to see a much higher voltage than it was designed to handle--same result.
                  --The cap was in a filter circuit, the rectifier (probably a bridge, but not necessarily) shorted and put AC on the cap. They don't last long with AC on them.

                  So, two out of three possiblities say something else caused the cap to blow, and I would think that is most likely. A schematic for the board would be wonderful, but without one, I'd look around the area where the cap is and see if there is some sort of rectifier circuit that could have shorted.

                  Where are you located?


                  • #10
                    Paul, correct me if I am wrong, but that board looks like it already was an aftermarket repaired replacement board. Does innovative Corp still not offer services on that board?


                    • #11
                      What scares me the most is how long the arc was. Look at the picture of the transistor... all three legs are missing! Whatever failed was able to sustain an arc long enough, both long time-wise and long arc-length-wise, to completely vaporize all three legs off the transistor. And to arc across the burnt off area on the back of the board. This isn't usually something I associate with excitation windings.


                      • #12
                        For less than the price of a new board you can buy my 251 and use it for parts. Mine works and runs well.


                        • #13
                          Aeronca41 I am in Lexington, Va. jjohn76 yes what I'm finding is that board was an update to the original 185468. Innovative Corp was who I sent it to originally and they said it wasn't worth fixing which might be true. I guess I was just looking for a second opinion before I totally gave up on. walker I appreciate it but you're a little far away and this was more or less a project that I thought I wouldn't have much in if I could look around and find what I needed. To be honest I wasn't really even looking for one when I stumbled across this "deal". A buddy of mine offered it to me cheap cause he didn't want to mess with it due to having multiple machines. I figured it was worth the money just to have a generator but it would be cool if it would weld also.