If I were going to do a cable tester over again I might not do it this way. Having a display that says “Cable OK” or “shorted” or “bad cable” with information on which conductor has the problem is kind of cool but really what does anything other than “OK” vs. “Not OK” do for you? If it’s not OK there’s not much you can do about it other than cut off the cable end and put a new connector on and test it again.
In that case just a simple circuit that puts current through LEDs and that fails to light some of the LEDs if there is a short or a break tells you “OK” or “not OK” in a much simpler way.
See: