[sdiy] Oberheim TVS Keyboard scaling

[gm]

So I'm doing the usual SEM repairs on a Two-Voice --
get to the final testing stage & notice that, while the oscillators on 
both SEMs track correctly in Unison mode, the two SEMs are several 
semitones out in Duophonic mode.  Further testing reveals that while I 
can get a three volt range from the bottom of the keyboard to the top, 
the third C is flat (along with several keys around it).

There are only two trimmers on the digital keyboard control module; does 
anyone know the correct procedure for scaling this thing?  All supply 
voltages (+/-18.5, +/-10, +9) are present and correct;  would like to 
eliminate the scaling as a cause for this before I start looking for 
other repair options.

Thanks.
~GMM