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MXR dynacomp (script) 1975 schematics

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  • MXR dynacomp (script) 1975 schematics

    Hello everybody

    Im new here (from paris)

    Im seaching for the schematics for my old MXR dynacomp (script) 1975

    I ave found the main IC (CA 3080) but a transistor is broken and has no reference on it.


    thanks

  • #2
    Is it this one: http://www.mif.pg.gda.pl/homepages/t...s/dynacomp.gif ?
    All transistors are 2N3904.

    Mark

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    • #3
      OUAHHH

      that is fast ...
      the only thing that whorries me is the sentence
      "the transistors may be 2n3904..."

      Thanks I will try and replace and give news

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      • #4
        Voulez-vous tout simplement que ça fonction ou qu'il est précis pour l'époque historique? Si tous que vous voulez est un Dynacomp fonctionnant, un 2N3904 sera suffit.

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        • #5
          Ok thanks I have got te transistors and te IC but now I see there is a little resistor on the oter side of the board is that normal ? I am affraid I have done some mods years ago. Do you have a photo of the board behind?
          Attached Files
          Last edited by tboy; 11-23-2008, 12:32 AM. Reason: attached image

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          • #6
            I have an old script logo one, the transistors on mine are MPS5172
            Code:
            http://www.onsemi.com/pub_link/Collateral/MPS5172-D.PDF
            a general purpose NPN.
            It's a good thing I opened mine up - the containing foam had gone rotten
            so due for a clean out.... I'll make up something to stop it shorting.
            Here's 2 pic's of my Dyna Comp PCB.
            Hope this is useful to you.
            Attached Files

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            • #7
              thank you, this is great becaus as I see there is a big modification on mine
              hope I can repair it now

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              • #8
                I know almost a decade has passed, but I wondered if you had any more pictures of the dynacomp. I've got the populated pcb with some wires and nothing else and there don't seem to be a lot of complete images on the net. Thanks, regards Chris

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                • #9
                  Originally posted by Chrisfromiowa View Post
                  I know almost a decade has passed, but I wondered if you had any more pictures of the dynacomp. I've got the populated pcb with some wires and nothing else and there don't seem to be a lot of complete images on the net. Thanks, regards Chris
                  What is it that you are looking for? The schematic will show you what is missing, (pot, switch , jacks) and how they connect to the circuit. It shouldn't be that hard to figure out where the wires go on the board and what they connect to.

                  I have an old one somewhere around here that i can pull apart for you, but it would be nice to know what you are looking for before spending a lot of time doing that.

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                  • #10
                    Hello Bill,
                    OK, what I have is thisClick image for larger version

Name:	mxr-dyna-comp-pcb-rear.jpg
Views:	2
Size:	32.5 KB
ID:	848143 what I'd hoped for was either another photo that shows where these wires connect, or just the names of them, ie Orange wire= V+, yellow wire= pcb in, Grey wire = pcb out, or whatever they are. Thanks

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                    • #11
                      Red wire (upper right in photo)= +9 volt battery Neg side of battery goes to ring terminal of the input jack

                      Yellow wire= pcb in Goes to one side of ft. switch and to input jack

                      Grey wire = Wiper of Sensitivity pot

                      Orange wire= CW term. of Sensitivity pot CCW terminal of sens pot not used

                      Red wire (lower right in photo)= ground Should be black wire

                      Purple = pcb out Goes to CW terminal of output pot

                      Let me know if there is anything that you don't understand or if there is something else you need to know.

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                      • #12
                        Thanks, you rock Bill!

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                        • #13
                          1976 MXR Dynacomp schematic attached.
                          Attached Files
                          "Everything is better with a tube. I have a customer with an all-tube pacemaker. His heartbeat is steady, reassuring and dependable, not like a modern heartbeat. And if it goes wrong he can fix it himself. You can't do that with SMD." - Mick Bailey

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