What was found
CREW REPORTED ON ROTATION, STICK SHAKER ACTIVATED EVEN THOUGH A/C WASN`T IN A STALL. SHAKER CONTINUED UNTIL POINT C/B`S WERE OPENED AS RECOMMENDED IN AFM. CREW ELECTED TO RETURN TO AIRPORT & LANDED UNEVENTFULLY. INVEST REVEALED THAT PRIOR TO FLT, PILOTS STALL PROTECTION SYSTEM IND NEEDLE SHOWING IN RED (PUSHER) ZONE AS SOON SINGLE CHANNEL SELF-TEST INITIATED, WHICH IS NOT PER AFM & SHOULD HAVE INITIATED SOME CONCERNS AT THAT POINT. IT IS BELIEVED THAT THE PILOTS SPS INDICATOR NEEDLE WAS IN RED POSITION AT ROTATION, WHICH GENERATED THE SHAKER ACTIVATION. THE SPS COMPUTER WAS REPLACED, FUNCTIONAL TEST WERE COMPLETED NORMALLY.