key down gate opens VCA4 in C107 to let through PW from Q106 LFO > 960 shift in so sequence plays as long as note is being held. Gate high also goes to Q128 letting A (0 volts) through to stage 9 in, when gate is low, 128 switches to B to stage-9 in, B is being fed 5V offset from 564 stage one out. Extra EG between gate and 128 control in helped when legato playing caused 960 to go right back to stage 9 and not run.