Micromoog Restoration Questions

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1

Hey Folks!
I’m restoring a very neglected micromoog. It was in a sorry state when I picked it up, but got it for cheap cheap cheap. I figure as a studio engineer/tech that this would be a fun project to get my feet wet in repairing an analog synth. I was scared as I’ve never worked on a vintage American synth before, but once I popped it open it made perfect sense to me. The simplicity and well laid out design just shows how much of a genius Bob Moog was.

So far I’ve recapped the whole power section and a good portion of the main board, replaced all the opamp ICs with quality ones I had kicking around my studio, hardwiring a bunch of broken molex connectors, fixing a bunch of shady looking traces, using a stripped out RJ-45 shield as a replacement grommet strip, cleaning out the spider webs and giving it a good clean, but amazingly the temperature CA3036 is still good as far as I can tell. Next step is to build it a new chassis out of some very nice quality mahogany or cherry.

Every function works perfectly now. Sounds great and the filter sweep is amazing.

Now here’s the issue. I can almost get it in tune, albeit 1cent plus (high b) or minus (low F) across the keyboard if I use the fine tune pot to tune the middle G#. During the oscillator tuning procedure, I can’t get the OSC HI trimmer to hit the high F exactly, it’s always a few cents sharp with it fully turned. I figure the next step is to replace the trimmers as I’m fairly confident that IC304 is not the issue.

Here’s the list of questions if you folks would be so kind…

  1. What make of trimmers did these use? What current manufacture of horizontal adjust trimmers would be a suitable replacement?

  2. Has anyone found a suitable modern replacement for …?
    -C212 (POLYCARBONATE- 0.27uF, 50V, ± 20%)- I figure the best modern equivalent would be a PPS capacitor, but no current manufacture has any specs like that…any suggestions?
    -C401 (POLYSTYRENE- 0.001uF (or 1000pF), 600V, ± 5%)

  3. If anyone has a replacement faceplate for one of these they are willing to let go, please let me know.

Thanks for your help!

2

Congratulations on your project micro! Its a great little synth that keeps amazing me year after year. Would love to see some pics when you finish the wood work.

Sorry I can’t help with the tech questions…

3

Thanks for the kind words! I actually picked up a piece of wonderful looking rough cut local cherry this morning. Luckily I have a neighbor with the full gamut of cabinetry tools. It’s going to be quite a sight when it’s finished.

This synth, even though not 100% yet, is making me consider selling off my digital synths and building a moogerfooger rig. This is the sound I’ve been looking for.

4

There is a great demo that Erick did on youtube using the cp251 and freqbox as a 2nd oscillator for his micro. His youtube name is rythmicons. If you think it sounds good now wait til you hear it with 2 vcos

5

There is a great demo that Erick did on youtube using the cp251 and freqbox as a 2nd oscillator for his micro. His youtube name is rythmicons. If you think it sounds good now wait til you hear it with 2 vcos

6

That is in fact the video that has made me so curious about the possibilities of the Micro. It just sounds too cool and seeing people with the moogermooger modular suitcase has my heart racing. I’m obviously very late to the party.

Now, say I wanted to use another manufacturers modular gear with the micro. Is all I need an attenuator for the CV out before I can start interfacing? Or do I also need to find a way to convert the s-trig to v-trig?

7

Heres that video, in case you are interested. The CP and Freqbox is almost like having a second synth.

http://www.youtube.com/watch?v=j_yao74ScZo