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Thursday, September 20, 2012

Lightning bolt 2, computers 0

I've had several occasions to learn the finer points about home security systems. When I last wrote about this, it was in the context of a house in which someone had used a switched outlet to drive the garage door opener, and then the security system installer used that same outlet for its transformer.

I had another opportunity in the middle of the night during an amazing thunderstorm. Everyone was asleep, and then the entire house shook -- **BOOM** -- and the alarm started going off in full-blown wailing siren mode. We sort of figured it was related to the storm but still had to check to make sure no doors had been opened and nobody had broken in.

After a basic security check, it was time to shut off the alarm, but it wasn't responding to its keypad. Indeed, the keypad was flashing its lights like crazy and was beeping like nobody's business. All the while, the whoop-whoop-whoop was going on right there in the hallway and outside too. I'm sure our neighbors loved it.

We had learned a bit about how the thing worked due to earlier encounters with line noise and knew how to disconnect it from the phone line, so we did that and dialed the company. They basically wound up talking us through how to pop the cover and pull the battery, but that didn't do it, either. We also had to find this power brick which had always just been in this one bedroom connected to nothing in particular, and then had to unscrew it from the plate and disconnect it. That shut it up at last. Apparently the installer for that house had decided to tunnel under the carpet in a nearby bedroom for juice.

That was enough to kill the beast, and Elvis stopped sending morse code messages through our keypads. We did without a security system until they could send someone out to replace the whole thing. It had taken a pretty good wallop from a bolt of lightning.

Of course, at the same time, I had a computer running with a modem connected to another phone line in the same house, and it nominally managed to live through this. Its power supply didn't crowbar, and it didn't even reboot, but my modem was never the same. It started misbehaving rather badly, and the machine also started throwing PARITY CHECK errors, and then the hard drive started acting strangely.

Our local shop took care of things and replaced the modem, a couple of RAM chips (good old DIPs) and gave us a newer drive, and that was that. This new 220 MB disk back in the days before MS-DOS 5.0 meant we had tons of 32 MB drives, but that was fine. (Note: as far as I'm concerned, DOS 4 never existed.)