I would not recommend swapping cables on the single head, as there is internal circuitry in the print head that is different from one side of the head to the other, such as head temperature circuitry. However, along that same concept, swapping the ribbons from the magenta/yellow head with the black/cyan head so the magenta/yellow channels are firing the black/cyan head and vice versa is a safe troubleshooting technique and should tell you if the head is a problem. Be careful about crossing the cables over, i.e., cyan cable to black side and black cable to cyan side. I had a customer do this without talking to me first and the result was sparks and smoke. Now they are sending me the head board to repair and have to buy a new head, as it burned out a contact on the printhead itself.