As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
A/F ARM FAILED ON TAKEOFF ROLL, ABORTED TAKEOFF AT 70 KNOTS. A/F SELECT ONLY. RETURNED TO GATE. REMOVED FROM SERVICE. REMOVED & REPLACED #1 PEC IAW Q400 AMM TASK 61-20-36-000/400-801. PERFORMED OPS TEST OF AUTO FEATHER AND UP TRIM SYSTEM IAW Q400 AMM TASK 61-20-00-946-044. ALL OPS TEST GOOD. RETURNED TO SERVICE.