What was found
PSC- AFTER ENG START AND EXTERNAL POWER WAS REMOVED, THE RT SIDE OF THE COCKPIT WENT DEAD. THE DC BUS LIGHT, NR 2 GEN LIGHT, AND BATTERY TEMP WARNING LIGHT ALL ILLUMINATED. NOTICED DARK SMOKE COMING FROM THE RT NACELLE IN LARGE AMOUNTS AND INCREASING IN INTENSITY. DISCHARGED NR 2 ENG AFT FIRE BOTTLE AND NOTIFIED CFR. SHUT DOWN ENG'S AND DEPLAINED PASSENGERS W/O INCIDENT. MX INSPECTED AND FOUND NO EVIDENCE OF FIRE. REPLACED 2431 -K2 CONTACTOR, NR 2 STARTER GENERATOR, NR 2 GENERATOR CONTROL UNIT, MAIN A/C BATTERY, NR 2 ENG AFT FIRE BOTTLE, AND NR 2 ENG AFT FIRE BOTTLE BLOW OUT DISK. ALL OPS CHECKS GOOD. A/C RETURNED TO SERVICE.