What was found
(CAN) NR 2 DC GEN HAD BEEN PLACED ON MEL JUST PRIOR TO DEPARTURE. INBOUND TO AIRPORT CREW LOST MANY F/O INSTRUMENTS: ADI, HSI, ALTIMITER STARTED GOING WAY UP AND DOWN, F/D FAILURES. CREW SUSPECTED THAT THEY WERE ON BATTERY POWER. BATTERY TEMP INDICATOR SHOWS BATTERIES AT 40 DEGREES. ONCE ON THE GROUND THE CREW FOUND NR 2 ADI AND NR 2 HSI CIRCUIT BREAKERS POPPED. MAINTENANCE REPLACED NR 2 ENG- START/GEN AND A GROUND RUN CARRIED OUT SERVICEABLE. COULD NOT FAULT- NO MESSAGES EVIDENT AT THIS TIME. FOR RELIABILITY OF DC BUS SYSTEM, THE CONTACTOR HEALTH CHECKS (TASK 2431/26X) TO BE COMPLETED AT NEXT HANGER OVERNIGHT. IF NFF DURING TASK 2431/26X CONSIDER REPLACEMENT OF CONTACTOR 2431-K21, P/N AJA4N176. MAINTENANCE TEST RESULTS: TASK 2430/26X CARRIED OUT. TASK FAILED AT STEP 13. FOUND .35 LOAD ON MAIN BATTERY WITH TRU`S OFF,#2 DC GEN OFF AND BUS TIE OFF. ALL INDICATIONS NORMAL FOR REST OF TASK. MAINTENANCE REPLACED LEFT GEN LOGIC RELAY. RUNS CARRIED OUT, ALL INDICATIONS NORMAL AS PER TASK 2431-K12. DC POWER SYSTEM CHECKED SERVICEABLE.