As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
THIS IS A CREW REFUSAL FOR INOP APU. DENMM EFS TO WORK DF935 TO TRY AND CORRECT PROBLEM. FOUND CONNECTOR P28 PIN 1 CONTAMINATED WITH DEBRIS. CLEANED DEBRIS, STARTED APU FROM BATTERY AND RAN ENGINES TRANSFERRED POWER FROM ENGINES TO APU NO SHUTDOWN OCCURRENCES. ASD RPT14 STILL INDICATES "LOSS OF SPEED" WITH APU CODE WORD 'ECB'. REPLACED THE APU.