What was found
FAULT ON NR 4 GENERATOR. UNABLE TO RESET IAW ABNORMAL CHECKLIST. SECURED ENGINE, MAINTAINED POSITIVE ENGINE OIL PRESSURE. INSPECTED MAIN OIL FILTER, FOUND NO CONTAMINATION. CHECKED OIL QUANTITY, RAN ALL ENGINES, ENGINE RUN WAS NORMAL. CHECKED AIRCRAFT WIRING AT GENERATOR RELAYS AND BUS TIE RELAYS. REPLACED NR 4 GENERATOR AND CSD. OPS AND LEAK CHECKED GOOD IAW DC8 MM 24-10 AND 24-20.