As you well know (well...as far as I've been able to tell! Maybe I missed it in the manual and am being an idiot here), there are no preset interval settings for the pitch bend wheel on the Oberheim SEM V. It's defaulted to a Major 2nd when not reassigned in the mod matrix. This is an inconvenience when compared to your typical modern virtual, analog modeling, hybrid, etc synthesizers, but is also a feature that IMO allows for some seriously fun tweaking of frequencies between the VCOs. After all, you can control each oscillator independently, giving them different amounts of response to the pitch bend wheel, and for that matter, you can assign all manner of other parameters to it as well. What may look like a glaring omission is really an intuitive look at analog style patch control. Plus, doing it by ear reminds me of setting the pitch bend on my MS-20 mini (I use a tuner when getting ready to record tracks with it).
But with that said, it'd be nice to be able to quickly and easily set the pitch bend to certain ranges, but as far as I'm aware, there is no reference for such a thing. So just quickly, going by ear and not by tuner, I figured out a couple.
In the Modulation Matrix, assign Source: Pitch Bend to Destination: VCO 1 + 2 FM. For Amount, try these values:
Octave = 0.418
5th = 0.209
4th = 0.127
These are probably slightly off, and I got lazy and didn't look up any others. If you happen to have a full set of values, or any others you'd like to contribute, put them here! Just let us know how you arrived at them (by ear, using tuner, set via equal temperament vs just intonation, etc if you're really advanced).
If nobody has any next time I stop by, I'll add a couple more.