Mxr Dynacomp

[BaaderMeinhof]

Hi!
I recently got an old pcb from a MXR Dynacomp pedal.
Now im facing the delicate problem of putting it together with new pots, jacks and housing.
Problem is that the pics im so long collected dont give it all away, and reading schematics only confuses me.

Is there anyone with pics from the inside of an old dynacomp that shows how the wiring should go?

Thanks beforehand!!

[ake]

uStomp Blog Archive MXR Dyna-Comp

[52 Bill]

Try these photos.

The pot on the top of photo is the output control the lower one is the sensitivity control. The jack at the top of the photo is the output jack the lower one is the input.

The input tip connection goes to the switch and to the middle top connection of the pc board.

Let me know if you need anything more explained.

[BaaderMeinhof]

Thanks for the help!!

Those pics were very clear and easy to follow.

Now i feel very confident and looking forward to get the parts and put it togheter..

Once again ...Many, many thanks..

[strat321]

by any chance to you have photos of the guts of younger models of mxr dyna comps? I have a green circuit board.
thanks

[oc disorder]

Have a look here
これってちょっと良さげかな〜♪ ぷちブログ　 MXR Dyna Comp Ross/ Fast Supra HiFi Mod


attached a pic but lower res , shows a mod but the majority of the board can be seen

[strat321]

MXR dyna comp 102

Have a look here
これってちょっと良さげかな〜♪ ぷちブログ　 MXR Dyna Comp Ross/ Fast Supra HiFi Mod

WOW that was my first post and a response already! thanks!

My M-102 does not look like this at all. Could it be an older model but not a 70's version? Mine has black, brown and yellow wires coming from the jacks.
As I am not the best at schematics, I'm hoping to get a photo of the innards.

thanks again.

[paynec]

Im trying to fix my sons MXR Dyna Comp. It has a green PCB but I'm not sure about the year. 05-16-01 printed on PCB, so maybe 2001??

I only have a bodgers knowledge of electronics, just enough to be dangerous to myself

The (470k) sensitivity pot was dodgy so i removed it, took it apart, cleaned the wipers, checked the resistance and put it back together.

I've re-soldered the pot but the box doesnt work at all any more. Bypass works fine, guitar feeds into amp, but when I push the button on, there is LED on but no sound output. It happens both with battery and transformer (seperately).
I have checked cables to amp and guiar are correct input/output.
I found a schematic but Im not sure its the correct one for my pcb https://www.electrosmash.com/images/tech/mxr-dyna-comp/mxr-dyna-comp-schematic-parts.png

Now, I have unsoldered the pot again to check the board. when I put an ohmmeter on the top pin where the pot should be (it is marked tp1) I cannot seem to find any continuity anywhere. The scheamtic shows the variable pot connecting to R17 and Q5 Q5 shows no short on any legs to the upper pin of the pot -but I dont see a broken trace.

R17, is connected to the middle and lower pin of the sensitivity pot (which are bridged).

Is Q5 the correct transistor for the other side of the pot for all schematic versions of the mxr dyna comp?

If it is, then I can just run a jumper wire. I recon I might have messed up a trace when I de-soldered the pot originally. If not, if someone can tell me where the pot trace leads to it would be much appreciated.

any help appreciated:

many thanks

[Helmholtz]

Please start a new thread.

My antivirus doesn't allow me to open the electrosmash link.
Please extract and post schematic.

Or even better make a drawing of the power supply input wiring.