What was found
THE CREW REPORTED A LOUD CRACKING FROM CIRCUIT BRAKER PANEL BEHIND. FIRST OFFICER`S DC GENERATOR NR 1 FAULT LIGHT CLICKING ON AND OFF. CREATED MULTIPLE ELECTRICAL PROBLEMS INCLUDING DC BUSS OFF AND INVERTER NR 1 LIGHT LOSS OF INSTRUMENTS AS A RESULT THIS ACFT HAS HAD MULTIPLE ELECTRICAL PROBLEMS THAT HAVE NOT BEEN PROPERLY ADDRESSED. THE ACFT WAS REMOVED FROM SERVICE. R & R DC BPCU AND AC BPCU IAW/JICC 24-46-83 RAI 10000 AND 24-41-83 RAI 10000. THE OPS CHECK WAS GOOD. THE ACFT WAS RETURNED TO SERVICE.