What was found
DURING APPROACH WITH THE LDG GEAR DN AND FLAPS 20/20, F/O GOT UNRELIABLE AIRSPEED ON PFD FOLLOWED BY SLATS/FLAPS SYS 1 AND 2 FAULT LIGHTS ON O/H. DISCONTINUED AP AND FOLLOWED QRH. WHEN THE SLATS/FLAPS CYCLED PER QRH, THE LIGHT/FAULTS CLEARED CONFIGURED AGAIN THE SLATS STUCK AT 15 DEGREES. FOLLOWED QRH FOR SLATS STUCK LANDING. ON FINAL AP FLAP HANDLE AT 40 DEGREES THE SLATS BROKE FREE AND WENT TO 30 DEGREES SLATS WITH 40 DEG FLAPS. THE LANDING WAS UNEVENTFUL AND SLAT/FLAP RETRACTION THE GROUND WAS NORMAL. REMOVED AND REPLACED SFCC'S,