As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STARTED APU, HAD BLUE LIGHT "APU GEN OFF BUSS" LIGHT UP BUT NO VOLTS OR FREQUENCIES. ACFT GROUNDED. UNABLE TO DUPLICATE DEFECT. STARTED APU, BLUE GENERATOR OFF BUSS LIGHT ON WITH GOOD VOLTS AND FREQUENCIES. GROUND VERIFICATION TEST PASSED IAW MM 24-21-00. NO HISTORY PAST 30 DAYS.