What was found
MCO - FLT 1263 - EN ROUTE FROM PHL, AT FL220, RECEIVED AN ALERT FOR CABIN PRESSURIZATION AS CABIN ALTITUDE CLIMBED ABOVE 10,000 FT. DECLARED EMERGENCY AND ACCOMPLISHED AN EMERGENCY DESCENT. BOTH TRANSPONDERS FAILED-NO FAIL LIGHT ILLUMINATED, CABIN CHIMES AND FORWARD SMOKE DETECTOR SOUNDING, SPEED BRAKE LIGHT GOING GREEN TO AMBER INTERMITTENTLY AND A/T AND TCAS FAILING INTERMITTENTLY. DIVERTED TO MCO AND LANDED WITHOUT INCIDENT. MX FOUND A DEFECTIVE C/B AT P6-1 PANEL, E-13 POSITION, NR 2 ELEC A/C BUS. R&R CIRCUIT BREAKER. ALL SYSTEMS CHECK GOOD AT THIS TIME. THE PROBLEM REPEATED THAT DAY. FOUND THE GROUND SAFETY SWITCH CYCLING BETWEEN AIR AND GROUND. R&R S105 GROUND SAFETY SENSOR AND M990 GROUND SENSING CIR