As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ADI MALFUNCTIONS SHOWING PIT AND ROL FLAGS, FIRST OFFICERS SIDE SHOWS 4 DEGREE PITCH LOW. FIRST OFFICERS COMMAND BARS OFFSET LOW WHILE CAPTAINS COMMAND BARS OFFSET HIGH. RETURNED TO SFO. TOOK OFF AND RETURNED SECOND TIME WITH SAME MALFUNCTIONS. REPLACED AHRS COMPUTER. PN 622-6190-204 SN 1981 UNABLE TO DUPLICATE SQUAWK SECOND TIME. REPLACED DPU FOR TROUBLESHOOTING. OPS CHECKS GOOD.