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Thread: MXR dynacomp (script) 1975 schematics

  1. #1
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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. #2
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    Is it this one: http://www.mif.pg.gda.pl/homepages/t...s/dynacomp.gif ?
    All transistors are 2N3904.

    Mark

  3. #3
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    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

  4. #4
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    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.

  5. #5
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    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 Thumbnails Attached Thumbnails p1040291.jpg  
    Last edited by tboy; 11-23-2008 at 12:32 AM. Reason: attached image

  6. #6
    Old Timer oc disorder's Avatar
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    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 Thumbnails Attached Thumbnails mxr-dyna-comp-pcb-front.jpg   mxr-dyna-comp-pcb-rear.jpg  
    nickb likes this.

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

  8. #8
    Junior Member Chrisfromiowa's Avatar
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    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

  9. #9
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    Quote 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.
    Chrisfromiowa likes this.

  10. #10
    Junior Member Chrisfromiowa's Avatar
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    Hello Bill,
    OK, what I have is thismxr-dyna-comp-pcb-rear.jpg 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

  11. #11
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    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.
    Chrisfromiowa likes this.

  12. #12
    Junior Member Chrisfromiowa's Avatar
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    Thanks, you rock Bill!

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