Discussion about the Korg PolySix synthesizer

The problem is that there is no guideline in the service manual for
calibrating the antilog amp (before the multiplexer).
I always wanted to find out about this in more detail because I'm sure this
will affect the tuning precision over the whole range. I once had a Polysix
on my desk with an antilog amp that was very mis-calibrated. It took me
ages to get it into an acceptable tuning: The voices were mostly hitting
the designated tuning "spots" but were out of tune in between. Imagine a
diagram of a sine function - the tuning felt like that.
 The Korg Trident manual has a procedure for this but it is not very
helpful (at least it didn't work for me).

This is also a circuit part that differs between the voice board revisions.

Perhaps it is possible to extract something from comparing it to the
service instructions of other synths from that Korg era. As I said there is
something about this in the Trident manual; and the MonoPoly manual also
has instructions (of course the circuit differs).

There must be some kind of procedure; I can't imagine they did this by
trial and error at the factory.