As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT NR 2477: NR 1 ARCDU FAILED. RAN THE CHECKLIST AND RECYCLED ON-OFF SWITCH. NR 1 ARCDU FAILED MESSAGE REAPPEARED 3 MINUTES LATER. MAINTENANCE REMOVED AND REPLACED CAPTAIN'S ARCDU. OPS CHECK GOOD IAW MTC 6238101. HGS OPERATIONAL TEST FAILED. AIRCRAFT DOWNGRADED TO CAT I. PLACARD REFLECTS THE SAME. MTX CONTROL NOTIFIED. AIRCRAFT RETURNED TO SERVICE.