As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ROTATION, WHEN SELECTING THE LANDING ''UP'', THE NOSE A & B SYSTEM RED AND GREEN LIGHTS REMAINED ILLUMINATED. CYCLED THE GEAR PER THE QRH AND NO GEAR MOVEMENT NOTED. RETURNED TO LAX AND WHILE ENROUTE LIGHTS EXTINGUISHED. NORMAL LANDING GEAR EXTENSION WAS ACCOMPLISHED.REPLACED NOSE GEAR A SYSTEM DOWN POSITION PROXIMITY SENSOR. CYCLED LANDING GEAR MULTIPLE TIMES. OPS CHECK GOOD.