Well, I'm not familiar with the exact circuit of the particular power supply in question, but all the power supplies I've seen are based on a voltage regulator IC. These IC's come in standard voltages like 5V, 6V, 9V, 12V, 18V, 24V... so if you want a "Replace this component dummy" answer then, in theory at least, you could swap out the 24V IC for the 12V one and be good to go. Just make sure to restore the heat sink with compound, etc. The IC could be either a TO-220 package
or TO-3
. Hit
http://www.digikey.com/ and look up your part number then find the 12v equivalent. It might just work if that's what you're really after.
If I were doing this, though, I'd just get a 12V/2A regulated supply made for automotive use and feed it from the 24V supply. A car battery is 14-15VDC and alternators can spike to 20V and higher so I'd think a regulated 24V supply wouldn't overtax one of good design. Just go to any car parts place that the kids go to. They're fairly common because they use them for in-car MP3, video games, PCs, and all that crap you shouldn't put in a car.
It's easy to define what you're willing to fight for; but what are you willing to stand for without fighting? What are you willing to lay down your life for?
