single field to dual isolated field alt

I asked for suggestions .. and now i am getting smart remarks ... FIRST of all .. parts that i have replaced i did not shot gun other than CHINA regulators .... ALL other components were for restoration purposes .. I know how to check volts/ohms/current draws... if i didn't ... i wouldn't be FIXING todays cars from my office for so called techs that cannot fix them in a dealerships... SO i think i know what i am doing as for as electronics ... AGAIN all basics are done ...THIS IS AN INTERMITTENT concern that all of a sudden happens ... by the time i catch it ... regulators circuitry is damaged ...
Again thanks for the BASICS ... I will let you know what the cause is once i get it resolved ...