Minimoog keys . . .
I recently found a decent minimoog D and have been trying to bring the keyboard action back to life. It takes patience but is basically straight forward to sort out I think.
First I removed the base and then the mod wheel module, and then unscrewed the four screws holding the keyboard mechanism in place. Between the screws and the mech there are some wooden spacing blocks, and they are different on the front and back so you need to mark them up!
Then I took off the key tops so I could give them a good clean. 30 years of finger grime is grim. It’s pretty straight forward, you just need to unscrew the flat head screw at the top of each key and then carefully slide the key tops forward.
The next step was to remove the springs at the back of the keys. There are actually two different strengths of spring, one for the black notes and one for the white. If you put them back the wrong way round (which I did) the action just feels all wrong. I just made a small pile for the black note springs and one for the white. Also care needs to be taken to not over stretch the springs (which I did) when they are being removed as they will deform and loose their springiness.
After that, I lifted up the back of the metal key bar to get to the key bushings and give the whole thing a good clean.
The stem at the back of the keyboard is sort of bent out so that the metal key bar is held in place, so quite a bit of force is needed to lift the key bar up. I took my time over this as the actual switching mechanism underneath looked very delicate, and I’m not sure those bits would be possible to replace!
Key bushings for this keyboard mech are pretty readily available. My keyboard was a bit clunky sounding and some of the keys were a little un-even in height. Theoretically you are meant to change all bushings at the same time so as to give an even feel across the keyboard, but I just changed a few at first as a practice run.
Once the metal key bar is removed it’s pretty easy to pull off the old key bushings, and then slide on new ones. However, once re-assembled the keys that I changed the bushings on were really sticky and sluggish. I think that sometimes when you get key bushings they are lubricated already, but mine weren’t, so I got some Dow Corning 7 Release Compound to lubricate both the new bushing and the old transparent plastic domes that are under each key. This is the lubricant recommended by a few sites I found, and seems to work well. I have read of other people using corn starch or vaseline as well . . .
Here is an old key bushing (front) and lots of dirt. The bushings do have a ‘right way up’, and it’s pretty easy to figure this out by looking at how the old ones are arranged. Take care when removing the metal key bar that the transparent little plastic domes don’t come off with them and disappear somewhere.
Next I took a look at the key contacts. I had a few notes that didn’t trigger properly and a few that didn’t hold pitch well when played. Both of these problems were sorted out by very carefully cleaning the contact bars. The contact springs look really delicate so I took some time over it. I just used cotton buds to wipe away some of the dirt and left it at that. I have read of people removing the whole bar for cleaning, but that seemed un-necessary to me given that it wasn’t that dirty. The ‘double’ contact bar is for gate triggering, and the single one is for pitch tracking.I’m happy to say that after about 4 hours of cleaning, the keyboard is in much better shape and the pitch tracking and gates are all working fine. Apart from the spring that I half broke… which is now living down on the little used F# at the bottom of the keyboard!