Does anyone have a good (engineering level) understanding on how the auto tune works on the OB-X

I have one OSC on one voice that is getting a strange auto-tune control voltage causing it to be out of tune. After swaping around op-amps to no avail, my next guess is a bad cap supporting the voltage at the op-amp.

However, I don't understand what goes on during an auto-tune. I assume it compares the OSC frequency to a reference signal. I don't understand who the comparison in made, or how the software turns off voices, gates the voice, etc...

Thoughts

Thanks.