As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER REMOVAL OF EXHAUST DUCT AND CORE ON APU FOUND SEVERE CORROSIONB ON FRAME (148N1606) AT STA 1992.8 APPOX 6 INCHES AT THE 6 OCLOCK POSITION (APPROX 4-7 O CLOCK) WAS FOUND FRAME, RING AND SPLICE WITH CORROSION OUT OF LIMITS EVALUATED IAW B757 SRM 53-00-07-1A, THEY WERE FABRICATED PER BOEING DWG 148N1606 REV G AND REPLACED IAW B757 SRM 51-40-02-OG