What was found
RIGHT MAIN LANDING GEAR WOULD NOT RETRACT ON TAKEOFF. RETURNED TO FIELD. REPLACED LANDING GEAR CONTROL BOX WITH SERVICEABLE UNIT. ALL LANDING GEAR OPS CHECKS GOOD ON GROUND. (P/N 12038594501) (S/N 24430031), (P/N 12038594503) (S/N 120353) ON.