What was found
AMBER FLAP FAIL CAS DURING CLIMB THROUGH FL390 WOULD NOT RESET. SLATS WERE AVAILABLE - REMOVED FLAP HANDLE CLEANED DUST OUT OF INSIDE WITH A SMALL AMOUNT OF AIR AND CONTACT CLEANER. REINSTALLED FLAP HANDLE I.A.W CE750 AMM TASK 27-51-00. REMOVED NC001 PCB. P/N OFF 6718150-6 S/N OFF 0102 INSTALLED SERVICEABLE PCB P/N ON 6718150-6 S/N ON 0357 INTO THE NC001 POSITION I.A.W CE750 AMM 24-53-00. PERFORMED SEVERAL OPERATIONAL CHECKS OF THE FLAPS WITH NO FAULTS REF CESSNA 750 AMM 27-50-00. AT CUSTOMER REQUEST, SWAPPED DAU 1 & 2 FOR FUTURE TROUBLESHOOTING I.A.W CE 750 AMM TASK 31-41-00. DAU 1 P/N OFF & ON 7013348-943 S/N OFF 56006321 S/N ON 100020606. DAU 2 P/N OFF & ON 7013348-943 S/N OFF 100020606 S/N ON 56006321.