[sdiy] Identification of an unknown MIDI CV interface

[brianw]

If there's an existing CV mixer in the Prodigy for VCO pitch, then the MIDI and local keyboard voltages could be added. This would allow the local keyboard to transpose the incoming MIDI.

It does seems that R104 and R105 make a pitch CV mixer, so an addition 120 kΩ resistor could be added for the ability to have local and MIDI active at the same time.

However, it might still be necessary to have a switch to disconnect the MIDI CV, otherwise the local keyboard would be transposed by the latest MIDI note (unless Note Off sets the DAC to 0 V, but that would not work very well with notes that have any Release time at all). Otherwise, you'd have to send MIDI Note number 0 or appropriate to reset the DAC to 0 V.

Brian


On Sep 27, 2022, at 1:00 AM, Florian Anwander <fanwander at mnet-online.de> wrote:
> Hi Brian
> 
> Am 27.09.22 um 01:22 schrieb brianw:
>> p.s. Florian, does this Prodigy MIDI-to-CV interface have the concept of Local Off? I'm trying to imagine what to expect when playing the built-in keyboard at the same time as incoming MIDI is being interpreted.
>> 
> There is a simple double pole single throw switch, that select between the interface and the CV/Gate from the keyboard.
> 
> I don't thinkg that there would be a software based Local Off too. I received the Prodigy for repair and the interface does not react on any MIDI information (at least I don't see any data stream to the DAC). The signal between the opto coupler and the processor is there, but nothing else. There is a momentary button on the modwheel panel, that switches an input of the processor to high; I assumed a "learn button", but none of several methods to use it seem to have effect (press, then send note; send note while pressed; same with controllers).
> 
> I have a very simple EPROM reader somewhere, but I have to check whether the old laptop with the corresponding DOS program still will run ;-)
> 
> 
> As the owner does not want to spend too much money (and the working time will be most of the costs) I will replace the interface with a new one assumingly.
> 
> 
> 
> And to the others: thanks for all the reactions!
> 
> Florian