What was found
DURING TAKEOFF ROLL PRIOR TO 80 KIAS, FIRST OFFICER'S EADI WENT BLANK WITH FLAGS IN VIEW, BAR WITH ATT IN VIEW, GA .AND INST 2 FLAG. THE CREW REJECTED TAKEOFF AND RETURNED TO BLOCKS AT KIAH WITH OUT INCIDENT. MAINTENANCE INSPECTED AND FOUND NUMBER 2 INSTRUMENT RACK LOOSE. MAINTENANCE RESECURED INSTRUMENT RACK OPERATIONAL CHECK GOOD IAW ATI DC8 MAINTENANCE MANUAL 34-01-07. AIRCRAFT WAS RETURNED TO SERVICE.