You find my answers written inline.

Best wishes
Dieter Doepfer

> I guess the jumper 13 is hidden under the midi board, (I have the v2)
> ...but looking for it I discovered

yes, it's right from the CEM3394

> JP14 and JP15

These are reset inputs for the LFOs. As it's a very special function planned
for the DARK MATTER expansion box they are not mentioned in the technical
document. A short circuit resets the triangle of the corresponding LFO (JP14
LFO2, JP15 LFO1). E.g. a momentary switch or an electronical switch can be
connected there. Do not apply a voltage. This may damage the circuits !

> ...and of course I'd love to know if there's a use for them.
> (uh, and any others I didn't see yet)
>
> Having the triangle-wave available seems like fun.
>
>
> many thanks
> andy