MXR dynacomp (script) 1975 schematics

[mathologie]

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

[MarkusBass]

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

Mark

[mathologie]

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

[Mark Hammer]

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.

[mathologie]

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?

[oc disorder]

I have an old script logo one, the transistors on mine are MPS5172

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.

[mathologie]

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

[Chrisfromiowa]

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

[52 Bill]

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]

Hello Bill,
OK, what I have is this 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

[52 Bill]

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]

Thanks, you rock Bill!

[g1]

1976 MXR Dynacomp schematic attached.