Saturday, January 11, 2020

Techs from the Crypt: Haunted Office

So at one of my schools, the principle jokes around about her office being haunted. Generally, if a weird problem can occur, it happens here. My main problem I originally had with this room was it took replacing her VoIP phone twice until there was no static. Two brand new phones did not work, but a random used one from another place worked just fine. On top of this, there was always a minor problem somewhere along the line.

So one day I am heading into work and I get an email. It was a long chain of emails forwarded to me that I didn't read right away and instead just saw the immediate message to change out her computer. Now for changing out an office computer, it is a pain. There are extra pieces of software that would need to be installed, some of which I don't do. So rather than bothering asking anyone, I do my usual of I'll deal with it when I deal with it. I grab a spare computer just in case and then skim the email chain.

The long story short is after we had new bus radios set up, they get static when anyone takes the hand-helds into the principles office. They think it is Bluetooth or something messing with it, which I can't say I've seen before and the computer doesn't have Bluetooth or a wireless card. I have a CB radio with built in Bluetooth and that doesn't cause any problems whatsoever. The reason they think it is the computer is because the static stops when it's off. Well, computers can be connected to and powering many other things, so that is not definitive troubleshooting.

I get to the school and she shows me what she does when it happens. Oddly enough, there was static in her office, but not out. So I stay in clear line of sight out the door and the range is far below what Bluetooth should do, about 10' at best had static. She did have a wireless mouse, so I unplugged the dongle. Still had static. I unplugged everything except the monitor, still static. I turned off the computer, static gone. Now this is weird and should not be happening. I turn the computer back on, no static until a certain point of booting up. This was really strange.

I proceed to dance around the room with the hand-held looking for any dead areas on the static. There were. It had very distinct, equally spaced dead areas. My random thought is that is very wave-like. I thought back to when the computer was booting up and when the static came on. There was a point where there was static, a space, then solid static. It was when the monitor auto-adjusted. I turned the monitor off, no static. Not anywhere in the room.

Here is my best conspiracy-theory guess. The monitor was a much older LCD display that uses a crap ton of power with a controlled refresh rate. I think that refresh modulation, or whatever, was going at a frequency with enough power through old enough electronics to generate EMI detectable within the frequency the hand-held was set for. Makes enough sense for me to say sure, why not. It is either that, or the monitor needs an exorcism.

So I grabbed a newer LCD monitor that weighed about 1/5th the original and put that in. No more static.

Let this story be a lesson to everyone out there. When repairing anything, actually troubleshoot the problem. If It wasn't for my reluctance to do something that would take a lot of time and effort, I would have wasted a lot of time and effort and not have a problem solved.

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