What was found
MASTER CAUTION RELAY (WIRING DIAGRAM 31-52-00 SHEET 1 - K28), LOCATED ON CIRCUIT CARD DB5 OF JUNCTION BOX 4 FAILED CAUSING BOTH MASTER CAUTION WARNING ENUNCIATORS TO STAY ILLUMINATED - NO RESET AVAILABLE. THIS IS A SINGLE POINT OF FAILURE FOR THE WARNING/CAUTION CONTROL SYSTEM. THREE INTEGRATED AVIONICS COMPUTERS FEED THIS MASTER CAUTION RELAY - SAME WITH THE MASTER WARNING. AFTER DOING A LIMITED INDEPENDENT SURVEY, I DETERMINED THAT THIS HAS OCCURRED ON SEVERAL OTHER AIRCRAFT.