What was found
CREW REPORTED UNCOMMANDED PITCH ON AUTOPILOT WITH EFIS COMP MON PIT AND ROL. ED1 WENT BLANK AND LOST AIRSPEED, PITCH AND ALTITUDE. F/O SIDE ED WAS INTERMITTENT. AIRCRAFT YAWED INTERMITTENTLY. CREW DECLARED AN EMERGENCY AND LANDED WITHOUT INCIDENT. MAINTENANCE TROUBLESHOT, REMOVED AND REPLACED AHRS 1 (ATTITUDE AND HEADING REFERENCE SYSTEM COMPUTER) AND PERFORMED CHECKS USING AIRCRAFT MAINTENANCE MANUALS. AIRCRAFT RELEASED FOR SERVICE.