As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ON TAKEOFF THE LANDING GEAR HANDLE CAME UP BUT THE GEAR DID NOT RETRACT. AFTER RECYCLING THE LANDING GEAR HANDLE TWICE, THE GEAR RETRACTED. THE MANUAL GEAR RETRACTION DOOR WAS RECYCLED IAW THE QRH. / FOUND PROXIMITY SWITCH ELECTRONICS UNIT INTERNAL FAILED. R&R UNIT PER AMM.