As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CAPTAIN'S EHSI WENT BLANK ON TAXI OUT. REPLACED GCU NR 1 (AUX GEN NR 1) IAW MM 24-30-02. CHECKED OPERATION OF POWER TRANSFER AT NP 70 PERCENT WITHOUT OBSERVING ANY ANOMALIES ON EHSI NR 1. CHECKS GOOD. PARALLELED AUX GEN'S IAW MM 24-30-02 ALL OPS CHECK GOOD AT THIS TIME.