- Warm up the instrument for 4 to 5 minutes.
- Tune The Source to a reference pitch using the rear panel FINE TUNE control.
- Touch program.
- Touch the STORE control and, while holding it down, touch the OSC 2 control in the Mixer section.
- Hold down the top key on the keyboard.
- Turn the Incremental Controller until the two oscillators are exactly in tune (the "beating" effect will stop).
- Touch any program number.
Source: Source — moog-source-owners-manual-rvgm (manual)