As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT BUG REPLACEMENT. LEFT BACK UP GENERATOR HAD DPI TRIPPED IN MUC, FILTER WAS REMOVED AND FOUND CLEAN. DUE TO REPETITIVE RESET OF DPI AND NO OBVIOUS FILTER BLOCKAGE LT BACK UP GENERATOR REPLACED. IN ADDITION TO LEAK CHECK ACP TEST OF BACKUP GENERATOR SYS ENG RUN. ALL OPS ARE NORMAL. NO CONTAMINATES FOUND. REPLACED BACK UP GENERATOR. OPS AND LEAK CHECKS NORMAL.