What was found
FLIGHT 2848 AFTER SHUTDOWN, WITH BOTH ENGINES OFF APU ON, GPU OFF, SPS1 INOP, SPS ADVANCED ALERTS ON EICAS & AOA COMPARATOR LIGHT ON PFD1 APPEARED. MASTER WARNING & CATION LIGHTS ALSO ALERTED & COULD NOT CLEAR OR SILENCE. WITH GPU ON, APU OFF WE WERE ABLE TO CLEAR & SILENCE THOSE WARNING CATION LIGHTS, EICAS & PFD1. THE ACFT WAS REMOVED FROM SERVICE. PERFORMED OPERATION TEST OF THE STALL PROTECTION SYS IAW 140 AMM 27-36-00. OPERATIONS CHECKED GOOD, NO DEFECTS NOTED.