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Thread: 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

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

    Mark

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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

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  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.

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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 Click image for larger version. 

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    Last edited by tboy; 11-23-2008 at 12:32 AM. Reason: attached image

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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 Click image for larger version. 

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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

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    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

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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.

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  10. #10
    Junior Member Chrisfromiowa's Avatar
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    Hello Bill,
    OK, what I have is thisClick image for larger version. 

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ID:	46377 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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    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. #12
    Junior Member Chrisfromiowa's Avatar
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    Thanks, you rock Bill!

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