Elektor Formant with step sequencer

video upload by MusicMiK

"Finally i got the missing VCO module for my Elektor Formant. And there also was "something else" in the box, which clearly looked like a step sequencer.

After finding out where the loose cables go and where power has to go, it needed some repair and now works quite fine. According to the chip labels, this thing might be built 1978, it's a very simple design with a 4520 binary counter, 3 4051 for potentiometer multiplexing and sequence control, together with a 4001 which generates the reset signal for the 4520.
The main clock comes from a NE555, the output buffers are TL071 now as one of the CA3130 was dead.

I don't know more about this thing, it looks a bit like a kit, but it also might just be built around a commercial PCB (single sided hand-drawn layout but white print on the component side). No signs about who made this thing, no schematics available (but in fact, it could be developed from scratch in less than a day i think :)

No, i didn't take care of dialing in any well-sounding melody, so it for sure sounds a bit strange..."