I have a blackout that has issues with the feature lights in what appears to be associated with row 7 on the lamp matrix. All of those are out. I recently had all the boards bulletproofed and repaired by a reputable tech in the hobby. He changed 5 driver transistors and got another problem where some of the feature lamps were burning up fixed. All the diodes appear to be fine as are the connections on the sockets. I think the issue may be in the harness somewhere. I checked the continuity from socket to socket on the yellow wires and everything seems to be connected. I am looking for some experienced advice on how to properly further troubleshoot the problem step by step from the connector on the driver board back to the playfield harness.