What was found
FLT 1053, AT APPROX 1:15 PM JFK-PIT, ON DESCENT FUMES/POSSIBLE SMOKE IN CABIN/COCKPIT, SEEMS TO DISSIPATE UPON SECURING LIVE TV. INSPECTED CABIN, COCKPIT & AFT MID & FWD AVIONICS BAYS, NO DEFECTS NOTED. FOUND CV C/B POPPED ON LTV RAC, ENERGIZED LTV SYSTEM. PERFORMED TROUBLESHOOTING CHECK OF EQUIPMENT VENTILATION SYSTEM IAW 21-28-00. GROUND SHUT OFF VALVE FAILED. TROUBLESHOT COOLING SYSTEM IAW E190 WDM 21-28-51. FOUND RELAY KO367 DEFECTIVE AND CAUSE OF C/B POPPING. REMOVED AND REPLACED RELAY IAW E190 SWPM 20-32-02. PERFORMED TROUBLESHOOTING CHECK OF EQUIPMENT VENTILATION SYSTEM AGAIN. NOW PASSED. COMPLETED CABIN CHECK OF LTV AND ALL CHECKED GOOD IAW LTV MM 44-20-10.