What was found
GEAR FAILED TO RETRACT ON TAKEOFF. WHEN GEAR HANDLE WAS RAISED, WE GOT TWO RED MAIN GEAR LIGHTS AND RT GREEN LIGHT. 10 SECS LATER WE HAD 2 RED MAIN GEAR DOOR LIGHTS, A FLASHING GEAR HANDLE AND 2 MAIN GEAR GREEN LIGHTS. FOLLOWED CHECKLIST AND LOWERED GEAR. THEN HAD 3 GREEN LIGHTS AND NO RED LIGHTS AND NORMAL GEAR HANDLE LIGHT. TROUBLESHOT AND FOUND PCB CARD 417JE TO BE DEFECTIVE. REPLACED P.C.B. CARD 417JE WITH INSPECTED UNIT IN ACCORDANCE WITH F2000 SP 20-500. PERFORMED FUNCTIONAL TESTS OF EXTENSION AND RETRACTION IN NORMAL MODE WITH NO DEFECTS NOTED.