The easiest and most secure way to MIDIfy a vintage poly synth is the use of reed relays. This has been proven today by Francois and me :) View with removed frontpanel - each key has a seperate pin, which is connected to -15V when the key is pressed. In parallel to these key->gate board connections, Francois has led through the inputs via ribbon cables: The backside of the synth with a nice view to the voice boards (sorry for the bad picture quality!) Core Module + 6 DOUTs stu