They could fix bad cores in a core plane. They cut the X and Y wire to remove the bad core. Then new X and Y wires were rethreaded through the old cores and the

They could fix bad cores in a core plane. They cut the X and Y wire to remove the bad core. Then new X and Y wires were rethreaded through the old cores and the new core. They tested planes after stringing the X and Y wires, before adding the sense and inhibit wires. If they found a problem after the sense and inhibit wires were threaded through, I don't know if they needed to remove them or if they could add a splice.