After our recent activity making the emergency ATX power supplies, I got a call one evening from one of the hams who couldn\’t get their salvaged 24-pin power supplies to work. It turns out that many of the larger computer manufacturers use their own proprietary pinouts. In this case, he got bit by a Compaq power supply. A good place to check to see if you can make a proprietary power supply work is pinouts.ru (yes, I know it is in Russia, but to my best knowledge it is not crawling with malicious software).