The original trigger voltage was +12v, with trigger time between 6-11ms, depending on the drum sound... There is +12v and ground going from the lower PCB to the top one via the large black and red wires on the far right of the circuit (see image below), so that is where I took the 12v from for triggering the circuits. You can also see that the trigger input points are spaced out along the front edge of the top pcb, super convenient! If I did it over again, I would have kept the original cables that connected the preset pattern rhythms to the triggers, and just added my own. Maybe I'll reconnect them eventually. You can also see where I had replaced all the trimpots with potentiometers earlier... A friend of mine gifted me an old drum machine when he was moving away: an EKO Rhythm Box. It was made in the late 70s, had 10 presets plus a level and tempo control. Obviously no midi etc. I fiddled with it a bit but found I couldn't do much with the sounds, so I took it apart. Each drum..