What was found
KSFB TRIP THE CREW REPORTED THAT UPON STARTING THE RIGHT ENGINE ALL POWER TO THE AIRCRAFT FAILED EXCEPT FOR STANDBY POWER. A GROUND POWER UNIT WAS CONNECTED AND SUFFICIENT VOLTAGE WAS SUPPLIED. WHEN RECYCLING THE POWER SWITCHES, THE AIRCRAFT WOULD BEGIN TO BRING THE BATTERY ON-LINE, AND THEN COMPLETELY DROP OFF. WHILE TROUBLESHOOTING THE PROBLEM MAINTENANCE DISCOVERED THAT A BUSS BAR FOR SUPPLYING THE NEGATIVE SIDE OF THE AIRCRAFT BATTERY HAD LOOSE HARDWARE. AFTER REMOVING THE NUTS FROM THE BUSS BAR THE BAR APPEARED TO BE ARCED IN HALF. THE EXTERNAL POWER RECEPTACLE, BATTERY GROUND TERMINAL LUG, AND EXTERNAL POWER J BUSS BAR WERE REPLACED. GROUND OPERATIONAL CHECKS OF THE ELECTRICAL POWER DISTRIBUTION SYSTE