The Moog Minitmoog is a rare preset synthesizer built by Moog in 1975. They weren't a big hit, and there are a lot more Moog Satellites out there. This is like the Moog Satellite, but has an extra oscillator, and a mechanical after-touch effect to add vibrato, sync, pitch bend, and other modulations. That feature is usually broken, and this was no exception.

I rebuilt the Touch Control (aka After-Touch) sensor, and now those modulations are again controlled by key pressure.

 

This is how it works: Under the keys is a hollow bar that's conductive on the inside, but not on the outside. A 100 KHz wave is fed to the conductive part. The bar, called the "Touch Sensor Bar", sits on top of conductive nylon, a wire, and foam rubber. Applying pressure - holding down a key at different strengths - creates a variable capactitor with the high frequency waveform (filtered down to triangle wave). This becomes variable control voltage that gets applied to oscillator sync, pitch, filter, or amounts of vibrato and tremelo.

 

 

 

-New keyboard bushings

-Wash and straighten keys

-Recap

-Solder fixes

-Oscillator calibration

-Pot/switch cleaning