As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIR TURNBACK, NOSE GEAR WOULD NOT RETRACT AFTER T/O. RECYCLED GEAR - BOTH GREEN & RED NOSE GEAR LIGHT ILLUMINATED. A/C HANDLED AS THOUGH NLG WAS DOWN. R&R NOSE GEAR LOGIC CARD PER MM. PERFORMED GEAR SWING; LIGHTS/GEAR CHECKED NORMAL PER MM. AT OAK, DURING DEPATURE, NOSE GEAR RETRACTED BUT BOTH NLG RED & GREEN LIGHTS ILLUMINATED. REPLACED S845 NOSE GEAR DOWN SENSOR (P/N 65C28018) & ACCOMPLISHED GEAR SWING PER MM OPS CHECK GOOD.