As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RETURNED & EMER DECLARED. LANDING UNEVENTFUL. ACFT WAS OVERWEIGHT. DURING INITIAL CLIMB OUT AT 500 FEET LT ENG BLEED OFF FOLLOWED BY LT PACK OFF. FOLLOWED QRH PROCEDURES. THIS WAS FOLLOWED BY THE RT ENG BLEED & RT PACK CYCLING ON & OFF WITH THE RT CTR FUEL PUMP CYCLING ON & OFF. PERFORMED FIM 36-10-00-815-820 & 77-22-00-815-R00. REPLACED LT ENG N3 TACH GENERATOR. PERFORMED LT & RT ENG HIGH POWER RUNS. SYS CHECKED NORMAL.