As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF, FIRST OFFICER'S STALL WARNING AND STICK SHAKER ACTIVATED. UNABLE TO ISOLATE WHICH SYSTEM FAILED. RETURNED TO MSP AND LANDED WITHOUT INCIDENT. REPLACED LEFT AND RIGHT STALL WARNING TRANSDUCERS AND SUMMING UNIT. SYSTEM TESTED GOOD.