What was found
DEN - FLT 439 - ON TAKEOFF, LANDING GEAR HORN SOUNDED ON RETRACTION. AFTER RECEIVING CLE, RT MLG SHOWED UNLOCKED, GEAR EXTENDED NORMALLY, AND DOWN INDICATION WAS NORMAL. INSPECTED, SWUNG GEAR, COULD NOT DUPLICATE. REPLACED PCB GJ21 AND GJ23 AS A PRECAUTION. OPS CHECKED GOOD.