What was found
DURING FLIGHT, LT MAIN BUSS, LT ESS BUSS, AND INVERT LIGHT ILLUMINATED. ALL CAPTAIN SIDE INSTRUMENTS INOPERATIVE. RAN QRH AND L MAIN BUSS, AND LESS BUSS WERE STILL OFFLINE, AS WELL AS CAPTAIN INSTRUMENTS. MAIN EMERGENCY, AND OTBD BRAKE ACCUMMNULATORS INDICATED ZERO. DECLEARED EMERGENCY. NO FLAP LANDING. INSPECTED, REMOVED AND REPLACED LEFT GENERATOR CONTROL UNIT, OPS CHECKED GOOD IAW AMM 24-31-10-02 AND AMM 24-30-00.