As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PDIS 793 22-10 4870 10FEB22 IND FACT U AUTOPILOT DISENGAGED AT FL 390. COULD NOT RE-ENGAGE LEFT, CENTER, OR RIGHT AP FOR REMAINDER OF FLIGHT. COMPLIED WITH QRH. T/S REF FIM 22-02 FAULT TREE 829 AND FOUND "ADC SYST L" MESSAGE. REMOVED AND REPLACED THE L ADC COMPUTER MANUFACTURED BY HONEYWELL P/N 404800-912 S/N 93013527 REF AMM 34-12-01-4 AND OP'S CHECK NORMAL. REF AMM 22-00-02-2 ACCOMPLISHED MCDP TEST 30 TEST 40 AUTOLAND TEST WITH NO FAULTS FOUND.