As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
APU DROPS OFF LINE AT ENGINE START. ALSO, APU WILL NOT HOLD ELECTRICAL POWER. *S/D* AFTER REMOVING CHRONIC APU, FOUND DRIVEN COMPRESSOR DIFFUSER WITH VERY CRUDE REPAIR TO LEADING EDGES OF THE VANES. ALSO, IGV VANES WERE VERY STIFF. CHRONIC APU REPLACED PER MM 49-11-01, AND OPS CHECKED GOOD.