My favorite story about X-10 is from one of my first months on the tech call phones here. I know it sounds like the text book tech call joke, but this is a true story, I was the tech not a friend or a friend of a friend. This is not an urban legend and Ian, our other long term tech was laughing so hard when it went down, I thought he would fall over.
I received a phone call from a customer, we'll call him Bill. Bill was ready to rip out all the electrical wiring in his house. He had installed X-10 products for their convenience and now they were making him insane. Some devices turned off right after he turned them on, some turned on by themselves, and others came on as if scheduled exactly at specific times day in and day out. Bill had ripped apart his house looking for the gremlin with the mini controller and pht02 timer.
While I am handling this problem and running out of ideas, I am also being called by Bob. Bob is having similar problems and I am beginning to think that I hate X-10 because these two customers are getting really frustrated by their nearly identical issues.
I immediately jump into the standard answers, remove any timers or controllers you have plugged in, change your house code. If you use A, use O now instead (my exact words). Check you logs for stray signals, unplug everything you own until there is nothing to control with X-10. The scarey part is, they changed the house codes, and it started again exactly as before on the new house code. They followed every direction to a T, not missing a single step. I spoke to them every day for over a week. I was about to pull my own hair out when Bob calls me up and says, That's it, i'm sending all this crap back. I am done, and so is my neighbor Bill. He is having the same problems as I am. They lived across the street from each other. They were triggering each others X-10 with their timers and remotes, Bill shutting off items that Bob is turning on, Bob shutting off items Bill is turning on....yes folks, I was officially in the middle of this. I instructed them to switch house codes, Bill going to A, Bob going to O, and if another neighbor buys X-10 they all need a PZZ01.
In my house it was my fishtanks, it took a little bit of work and effort, but the payoff was excellent. I couldn't have done it without a tester.