Realistic MG-1 Synthesizer Restoration Project

(note: I originally wrote this in 2006 and had it posted elsewhere)

Sometime in 2005 I bought a Realistic MG-1 via EBay, because I wanted an analog synthesizer to play around with. I’d seen an analog synth at the Trading Musician which I thought was awesome but too expensive. I don’t remember now what it was, I think a Boss or a Roland or something? Anyway, not being able to find it again I opted for the MG-1, as it was cheaper than a Moog Rogue but nonetheless very similar to one.

The MG-1 I got had been described on ebay as having a broken key, but otherwise in good condition. When it arrived I noticed it did indeed have a broken key, but it also smelled bad and didn’t work very well. Notes would drift wildly when played, so it was pretty much not usable as an instrument. Upon opening it I discovered that it was full of fuzz, hair, and mouse “leavings” (both types). Apparently a mouse had lived in it for a while, who had also bitten off the insulation from a lot of the wiring. The synthesizer also suffered from a well-documented problem that MG-1s often have of foam decomposition, where foam material used to keep dust out of the controls had turned into sticky crap.

some of the rat's nest, plus broken key

yes, that is disgusting. Note insulation falling off wires

some of the goop, though the larger foam bits are removed by this point

This was going to be a big project. I had already overspent a bit to get the MG-1, so I was determined to get it working. The first thing was to clean it. I spent a couple of months taking the whole machine apart and cleaning it. I scraped as much of the goop off as I could and used windex, which is probably not the best thing to use, but it worked.

keyboard contacts and lower PC board after cleaning

Much of the metal case had surface rust inside it, so while I was at it I washed and sanded it, and then painted over it with rustoleum. If I recall correctly I ran a lot of the non-electrical parts through the dishwasher, and washed the plastic keys in the sink. I repaired the broken key with a piece of light plywood.

upper case half after sanding, before paint

lower case half, after sanding, before paint

lower case half, after paint, with keyboard frame and PC board reinstalled

the broken key, now fixed. You can see some of the upper PC board in the background has been cleaned as well as I could get it

Instead of replacing the chewed-up wiring, which would have been a pain, I just used electrical tape to reinsulate the damaged bits. The mouse hadn’t severed any of the wires, and they’re color-coded. Where do you get color-coded wire? I don’t know. I’m also lazy.

I cleaned the pots and sliders with Radio Shack contact cleaner, and put the machine back together. I plugged it in, and.. well, it sounded exactly the same as before I started. But it smelled better. At this point I bought user and service manuals, and schematics, from an online resource, and then I stopped.

I left off the project in October, and put the Moog away so I could pretend it wasn’t there. A couple of weeks ago I decided I’d accumulated enough test equipment to finish, and spent several nights going through the calibration procedures, which weren’t really that hard. It took some figuring out what “Electrical 0” is and how it differs from “Electrical Center,” plus some of the filter calibration section is still confusing to me, but in the end the unit works much better. Finally, I sprayed the controls with CAIG DeOxit, which I hear is supposed to be really good at deoxidizing and preserving electrical contacts. The only problems left with the synth are as follows:

* notes will continue to play, and then drift in pitch, after you let go of the keys, though at a much reduced volume. It had done this before, though the pitch drift was much faster. The output at this point might actually be within the normal signal-to-noise ratio, which I have yet to test.

* if the keyboard tracking is set to continuous, and you play a note, the note will very slowly drift up in pitch. If you hold the note down, it will stay in pitch just fine. This is an improvement over the unit’s pre-calibration condition where the notes would drift all the time, and at a faster rate, though it might still not be correct.

These issues suggest that some components might need replacing, though the problems aren’t severe enough that the synth is unusable. I plan to make some recordings with it now, at which point I’ll have a better sense of whether I should pursue buying parts.

the completed synth, put back together

 

Update: 9/6/2006

I’ve now made some recordings with the MG-1, and I’m liking it quite a lot. It actually stays in tune very well, from day to day even. That’s probably because the temperature in my basement is pretty constant.

Update: 12/19/2011

Some tracks from my last solo album feature the MG-1:

Apartment

Tiger Nightmare (in the bass)

Some MG-1 links:

This site here helped a lot while I was doing the restoration: http://www.kleonard.com/gear/mg1.htm

Naturally there’s a Wikipedia page now:
http://en.wikipedia.org/wiki/Moog_Concertmate_MG-1

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