What was found
WITH RT ENGINE RUNNING AND RT GEN ON-LINE, GEN ASSIST START WAS OPERATIONAL. IF LT ENG WAS RUNNING AND LT GEN ON-LINE, ATTEMPTING A RT START WOULD CAUSE LT GEN TO DROP OFF-LINE AND RT ENG WOULD NOT ROTATE. T/S TO A CT3 (LT GROUND FAULT XFORMER) WHICH HAD CHAFED AGAINST LT ENG COWLING ATTACH BRACKET AND HAD BEEN RENDERED USELESS. REPLACED LT PYLON CT3 GROUND FAULT XFORMER WITH NEW PART, SAME P/N, AND SYS WORKED PROPERLY. INSPECTED RT GROUND FAULT XFORMER, FOUND SIGNIFICANT CHAFING AGAINST THE RT COWLING ATTACH BRACKET. REPLACED RT PYLON GROUND FAULT XFORMER WITH NEW PART, SAME P/N, OBSERVED OTHER CHAFING OCCURRING ON BOTH COWLING ATTACH BRACKETS.