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Mesa m3 carbine fix advice

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  • Mesa m3 carbine fix advice

    So my bass players amp started to make noise whenever he played certain notes or when it was bumped.
    I took the cover off and performed chopstick tests on the components and eventually found that the lead was broken off at the board on one of the driver transistors on the power output board.
    So Mesa's are kinda hard to work on and there is always something that makes it difficult to get full access so I managed to glob some solder on the broken lead from the top and weld it to the top of the hole in the board. And... viola it works now.
    Do you think it would work long enough for Saturday's gig and maybe the following Saturday also? I don't really expect this to be a permanent fix.
    The transistor in question is a MJE 15034 and is available from Mouser but might take a while to get here.
    Also if anyone has a schematic that would be nice also.

  • #2
    Can you post a picture of the repair?
    "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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    • #3
      Might take a little while let me see what I can do. Gotta charge up the gopro.

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      • #4
        I've gotten away with that sort of temporary fix. If it was a clean re-solder job and both sides of the break remained in place (lead wire didn't shift), probably good until you can replace the device. Visual aids are always good to keep in the files. I checked to see if I had the service documents, but only had the user manual.
        Logic is an organized way of going wrong with confidence

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        • vintagekiki
          vintagekiki commented
          Editing a comment
          I turned over the internet only the user manual.

      • #5
        Ok here is my pic. Not great but the soldered lead is just in front of the end of my chop stick. You can just see the glob of solder.

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        • #6
          Is there room between the heatsink and the board on the transistor? I can't tell from the picture. If there is enough room, I would carefully remove the transistor all together. Cut off all of the legs even with the broken one and then reinsert it into the holes. That only works if the leads will remain long enough.

          Otherwise, what I've done in a pinch is take a piece of lead from something else (like a larger wattage resistor). Bend it like a hook. Do the same with the remaining transistor lead and loop/crimp them together to extend the transistor lead. Solder the loop joint together. Then, reinstall the part. That way the joint isn't dependent on solder only.
          "I took a photo of my ohm meter... It didn't help." Enzo 8/20/22

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          • #7
            Thanks Nevetstab...I thought someone here might have done that in the past.
            So ... TD ... if I had enough lead to hook on an extension I would call it a good repair. The lead broke off at the fat part of the transistor. Also, you guys probably don't think twice about cutting wires to get to the bottom of the board but I hate it. This amp was close to being easy to flip up the entire output assembly except for the shielded signal wire from the pre-amp board. You can see the grey signal wire routed through the panel on the bottom right. Of course that wire is just barely long enough. So I tried to solder from the top.

            One last thing. I also tried searching for the schematic and found nothing but the board has

            "Mesa SSP M6-A 2007 DVR" printed on it. Maybe it is similar to a M6 Carbine.

            I'll update whether or not this worked for two gigs in a couple weeks.

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