This set of videos, via DinSync, shows you how to add control voltage (CV) inputs and outputs to a Roland MC-202, turning it into a semi-modular synthesizer.

The first video, above, shows how to add CV inputs for VCF frequency control and PWM amount.

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

This video shows how to tap into an extra waveform on the Roland MC-202 and what you can do with it once you’ve done so.

Finally, this video demonstrates how to add LFO and envelope CV outputs.