[sdiy] Oberheim TVS Keyboard scaling

[Roman Sowa]

I would start checking all the 4030 gates in the keyboard scanner. If 
one of them is faulty, few notes will play wrong tune while most of the 
keyboard range is OK.
Just my wild guess at this time...

Roman

W dniu 2014-07-30 09:29, gm pisze:
> 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
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