What was found
EICAS MSG L GEN OFF DISPLAYED. GEN OFF LIGHT ILLUMINATED. OPERATED NORMAL AFTER RESET. CREW COMMENTS: REPEAT GRIPE. LEFT GEN CONTROL OFF LT ILLUMINATED ON CLIMB-OUT. RESET NORMAL. LEFT GEN TRIPPED SECOND TIME. APU STARTED FL370. BPCU SHOWED "OPEN PHASE TRIP" AND "GEN-FDR" MSGS. REPLACED LEFT ENG GCU. BPCU BITE TEST IS OKAY. REPLACED LT IDG. OPS CKS OKAY. REPLACED NR 1 GENERATOR CONTROL BREAKER. ALL CONNECTIONS SECURE WITH NO EVIDENCE OF ANY ARCING OR DISCOLORED LUGS AT CONNECTION POINTS.