Computer Power
Main power control for personal computers come in two basic configurations/standards. AT and ATX (Well, there’s a lot more to those than the way the power supply works, but that’s the part I care about here).
AT is the way the older computers were connected. The power switch is a physical connection. You have a two-way switch, with an ON state and an OFF state. You move it to on in order to turn the computer on (surprised?), and to off in order to turn the computer off. The main advantage of the system is that you have full control of whether power is on or off. The disadvantage is that you have to press a switch in order to turn the computer off once you’re done with it. This never seemed problematical to me, but since they later developed a solution, I guess it was a problem.
ATX is the newer type. The switch is electronic. You only have a single button on the computer, which is used both to turn it on and to turn it off. This allows you to turn the computer off by software, so your computer’s operating system can provide a shut-down option that actually turns the computer off. No need to press buttons or anything tedious of the kind. The disadvantage is that it sometimes doesn’t get turned off due to a variety of reason. And then instead of flicking a switch, you have to press the stupid button for about 8 seconds until something realizes that you actually want it to turn off.
Way of the future…
We’re upgrading a system for a client. One of the changes involved is an upgrade to the computer. This is an industrial system, and we’ve ordered a new board that will fit the existing chassis and have enough extension slots for all the cards we need on it.
Before replacing the board in the chassis, we took a look at all the connections. Next to the power connections there was a jumper used to choose between ATX and AT modes. The existing button and power supply are AT. Next to the jumper there was a mode printed on the board. The jumper should be open for ATX and closed for AT. So far so good, we need to close the jumper.
Well, surprise. Instead of a jumper, there were two holes in the board where a jumper could be fitted, but no actual jumper. If we want one, we need to solder one in ourselves. And since not having a jumper means it’s effectively open, we want one.
It’s a real nice feeling, to take a brand new computer board, and start soldering stuff into it. Great way to ruin it before we can even check it. Our electronics engineer was thrilled.
And to add insult to injury, the board’s manual clearly listed that the closed option is the default one. Yea, right.
Anyway, jumper soldered and closed. AT power works fine.
December 5th, 2004 at 15:58 EET | Categories: Web |
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