As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER ENGINE START ON PUSH BACK. NR 1 ENGINE GEN WOULD NOT COME ON LINE. VOLTS/FREQS CHECK GOOD. ACFT GROUNDED. PERFORMED FIM TASK 24-21-00-810-807 GCB/APB FAULT. R & R NR 1 ENGINE GENERATOR CONTROL UNIT REF MM 24-21-81-400-801. OPS CHECKED GOOD.