What was found
LEFT MLG LANDING GEAR RETRACTION: UNABLE TO RETRACT LANDING GEAR ON TAKE OFF UPON TAKE OFF THE LANDING GEAR HANDLE WAS LOCKED IN THE DOWN POSITION AND COULD NOT BE MOVED TO THE UP POSITION. NO CAS MESSAGES WERE DISPLAYED OR ANY OTHER INDICATIONS OF A PROBLEM WERE PRESENT. REMOVED INOP LANDING GEAR MODULE PN H218B SN 00203 AND INSTALLED CUSTOMER SUPPLIED OVERHAULED LANDING GEAR MODULE PN H218B SN 00958. IAW CE-680A AMM 32-30-30. NO DEFECTS NOTED. OPS CHECK GOOD.