Look, it's just a switching mode power supply. There's no magic about attaching a motherboard. The reason Ben's trick below works is because sometimes they cross couple the current limiting / protection circuitry. Some chips that require both +5 and +/-12 will die if one rail dies, so the conservative P.S. designer will kill the whole supply rather than let one rail stay up and kill chips. An incandescent bulb is a bad choice, though, because they are usually 1A bulbs, and you're probably drawing a lot more current than you need to keep the supply on (and making heat, and reducing the available power you have at your disposal before you eat a fuse.) Probably a 1k resistor is more than sufficient. If you can, get a potentiometer, and find the minimum value that keeps the supply alive and then add 15-20%, and there you go. 15 minutes with a voltmeter, and you'll have a bunch of wimpy but utile bench supplies! Phil Mendelsohn On or about 20 Jun 2001, Ben Kochie is alleged to have said: > -----BEGIN PGP SIGNED MESSAGE----- > > there are some supplies that don't like to power up unless there is > something attached.. sometimes sticking a small 5v and 12v light bulb on > some of the motherboard output lines can do the trick. > > Thank You, > Ben Kochie (ben at nerp.net) > > "Unix is user friendly, Its just picky about its friends." > > On Wed, 20 Jun 2001, Brian wrote: > > > Here at work we often have to scrap old non-booting systems. I'd really > > like a nice 12 volt power supply at my desk but I don't want to have to > > attach a mobo to it. Is there any way to get the power supply to run on > > its own? > > > > The only info I can find is for ATX power supplies (which is as simple as > > jumpering two pins together with a paper clip) but nothing on AT power > > supplies. Anyone have any idea how to accomplish this? > > > > And yes, I know they say not to do it because you may damage your power > > supply, but I have an overstock of these 145 watt units so I don't care if > > I destroy a few trying :-) > > > > -Brian > > > > > > _______________________________________________ > > tclug-list mailing list > > tclug-list at mn-linux.org > > https://mailman.mn-linux.org/mailman/listinfo/tclug-list > > > > -----BEGIN PGP SIGNATURE----- > Version: 2.6.3ia > Charset: noconv > > iQCVAwUBOzDaustpDhsSpvgtAQG40AP+I9MRk9NCuRp7+qNWYSujDlIrq1ecqbUd > gfeeP3SILHHUPTt1jSzGwbbZL+DkhhyRJ7AH1j5FvCxk3EFqTJ6ju+YiZgfqv+TU > phInDSuqa/7Mx5ZB/LQHWGznZLDBTd1UIheKrV3drGVfFjrGPMKNv5Ln67Gi9pKW > sKB3bzyPcFI= > =1Irm > -----END PGP SIGNATURE----- > > _______________________________________________ > tclug-list mailing list > tclug-list at mn-linux.org > https://mailman.mn-linux.org/mailman/listinfo/tclug-list > --Begin signature-- X ---End signature---