Replaced F301 and print head, ensured ink flow to and through the regulators, and re-assembled everything. Printer powered up and all functions work, no errors, but no ink of any color comes out, even after multiple print checks, cleanings, and printing test pages.

If it is a bad, non-conducting cable trace, I would expect it to throw an error, but it does not. Before I take it apart again to continuity check from mainboard connector to end of ribbon cable trace, has anyone out there seen something similar or have any thoughts other than the obvious possible faulty mainboard, cable, and print head? E.g., why no error(s), all other functions work, etc.? Why no ink of any color? If the 'burnt' trace is common to all colors, e.g., ground or power to print head, why doesn't the mainboard detect a non-powered / non-functioning print head?