- Set CUTOFF FREQUENCY to -1, FILTER EMPHASIS to 10, and AMOUNT OF CONTOUR to 0.
- Turn KEYBOARD CONTROL switches 1 and 2 ON.
- Turn on the A-440 switch.
- Depress the third 'A' key from the bottom of the keyboard.
- Adjust the CUTOFF FREQUENCY control for zero beats (1760Hz, two octaves above 440).
- Depress the low 'A'.
- Adjust the Filter Scale trimpot (on Filter Board) for zero beat (440Hz).
- Repeat steps 4 through 7 until the filter tracks accurately over three octaves.
Source: MINIMOOG — minimoogservicemanual (manual)