I can see how only 1 would die if the actual port had a problem. If all the digital inputs died, that'd be easier to figure out... like a bad power supply for the digital board or something...
I kept thinking I might have a spec of dust causing the problem.. but, nothing gets moved, it's all been connected the same way for several months and hasn't been moved... Plus, it's all connected to a fairly large Tripplite battery backup/voltage regulator... and it stays fairly clean. There's no dust on anything.
It's just frustrating that it was instantly isolate-able to the port itself. I think I have a coax output from the cable box. If so, I might be in business again. I hope so. The last thing I need is another revamped project.