MS-20 Mini tune and scale adjustment
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I sometimes have to re-tune my MS-20 Mini. The pitch scaling is incorrect, and
has to be adjusted. Sometimes on both oscillators. To do this I set up a tuner
next to the speaker and start playing octaves. I turn the scale trim pot until
the octaves are clean, and then I move it to the correct base pitch with the
tune trim pot.

Usually I just poke at the trimpots until I find the correct ones but the last
time I did this I wrote the numbers down:

    PT3 - tune osc1
    PT1 - scale osc1
    PT5 - tune osc2
    PT4 - scale osc2

The trim pots are located on the back of the board that sits under the panel
and are easily accessible by just removing the back panel.