As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ABORTED TAKE-OFF PRIOR TO 80 KNOTS, EFIS COMP MON HEADING. MESSAGE CLEARED AFTER EXITING RUNWAY. BRAKE TEMPS: 3,3,4,5. UNABLE TO CONFIRM WHICH SIDE OFF PRIOR TO RUNWAY EXIT. CAPTAIN'S SIDE 4 DEGREE DRIFT AFTER ONE MINUTE AFTER EXITING RUNWAY. *********AIRCRAFT REMOVED FROM SERVICE********* REMOVED AHRS 1 AND FOUND TRAY DIRTY. CLEANED CONNECTION AND TRAY AND REINSTALLED AHRS 1. OPS CHECK GOOD, CONFIRMED HEADING IS NOT DRIFTING AS NOTED IN DISCREPANCY. WORK PERFORMED IAW AMM 34-21-01 AND ESPM 20-17-10.