As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AUTOPILOT AND HSI COUPLED TO C/P SIDE, C/P ALTIMETER STEADY AT 36000. STBY ALTIMETER STEADY AT 36000. PILOTS ALTIMETER RAPIDLY FLUCTUATES +/- 100. TROUBLESHOT AND FOUND ADC NOT PASSING TEST, REMOVED NR 1 ADC AND INSTALLED ADC . PERFORMED A SUCCESSFULL OPS CHECK. REF 800XP MM 54-10-15 COMPLIED WITH FAR 91.411, 91.413, AND DATA CORRELATION.