Troubleshooting Techniques: Dealing with Digital | Tech, No Babel

Transcript: There are some unique challenges with digital. With analog, things would gracefully degrade. You might have noticed this if you don’t have a cable television subscription, and when there was the digital transition you got one of those boxes, you plugged in your rabbit ears, and … I had this station before and now I don’t. Or maybe you’ve run into a problem where you used to run a VGA cable. You could run it, and maybe it wasn’t nearly as pristine as it was when it left, but the signal was fine. Most people couldn’t tell the difference. You probably could but most people couldn’t. Then you went over to HDMI or something and all of a sudden, doesn’t work. It either works or it doesn’t work. That’s what we want to talk about today is the challenges of dealing with a signal that either works or it doesn’t work, and how you deal with that.
The first thing I want you to consider is are you in a situation where perhaps analog, even though older, is the better solution. For example, a lot of people lost access to television stations when they went digital. That’s because analog was a somewhat better solution for their perspective. Now from the perspective of getting a lot of content into a smaller amount of bandwidth, not a good solution. But from the perspective of getting television stations that you maybe probably shouldn’t get, it’s a better solution.
Same way with sending a video signal over a longer distance. If you have a situation where you’re actually stretching things farther than the spec, if you really can’t quite get it there, analog is going to give you something, versus digital, which will give you nothing. That’s the first thing to consider.
Another challenge is that the difference between works awesomely perfect and just barely works? Totally imperceptible. You can’t tell if something just barely works because it’s either there or it’s not. There’s no gradation. There’s no fuzziness with digital. It’s either there or it’s not there. Now you might get a situation where it tries to be there and then it disappears. Then it tries, then it disappears. That happens, but in general, that’s a very fine line. It typically is the case that it’s either there or it’s not there.
Just barely working and just barely not working might be just a little bit of corrosion on a cable away. It could be that something gets a little oxidized. An amplifier gets a little bit weaker. It could be any of those things that cause something to just barely not work. I want you to consider that as you’re troubleshooting. That you’ve got another layer of complexity because just barely doesn’t work looks like not plugged in at all, not in the system at all, though consider that.
Now if you’re in a situation where something just barely doesn’t work, a good way to get past that is some of the techniques we’ve talked about before. You can short-leash it. You can simple it down, though short-leash it, use a much shorter cable and see if it works. If it does, you might be in a just barely doesn’t work situation. Simple it down. Remove as many pieces as you can. See if it works. If it does, you might be in a just barely doesn’t work situation. I want you to consider those as solutions as well.
Also consider that since digital either is there or is not there, little things can affect it. Again, along the lines of just barely doesn’t work and just barely works, what if … This happened to a buddy of mine. He was installing a system with HDMI, and whenever the HVAC system would kick on, then he would lose the signal. There was just a little bit of interference in the electricity. He just made the power just a little dirty, not a lot, a little bit. He was in a situation where when he installed it, it worked perfectly fine. The church didn’t have the HVAC on during the week because it was just one guy. Why waste the money? On the weekend when the people would show up, they would turn it on and it would quit working. Then it would. Then it would quit working. Then it would work again. It was the hardest thing to track down because just an intermittent addition of the HVAC system would cause things to quit working.
That’s what I want you to consider, that with digital you can get a pristine signal, but minor annoyances in an analog world are in fact a big deal in a digital world. That’s why if you frequent any of the church tech forums like I do, you’ll hear people that say, “Well it worked fine for six months.” It might have just barely worked for six months. Or, “I don’t know what happened. It was not working. I didn’t do anything and then it just started working.” Just barely working. It looks great, but just barely. That could be a DA, distribution amplifier, that is giving up the ghost, and as it is, it’s getting a little bit more power from the power supply. Intermittently better. It happens. That’s some of the downsides of using digital. I hope that helped you. I hope that now you have a better understanding of some of the stuff that’s going on with digital versus analog systems.