Have hit something of a wall and maybe someone can help.
I need a 12-volt DC power source for a mega-LED project (figuring ~10a). Naturally thought of using an old computer power supply. Was given two but when I began looking them over found they weren't ATX power supplies and had weird wiring in the 20-pin connector (lots of brown wires). Opened one up and fiddled around; using the standard web pages as guides (10 ohm, 10 watt sandbar resistor on the 5v line for load -- I particularly liked this one: http://www.instructables.com/id/ATX-...ly-Conversion/), was able to only get it to produce 7 volts on the 12 volt leads.
Frustrated, turned to CL and bought a new ATX PS for $10 yesterday. All the wire colors matched the colors the web pages talked about and wired it up accordingly. Nothing. Ran across an oblique reference to the 3-volt rail needing a load and added that (used a 12-volt auto lamp, because that's what I had laying around). The result was that the fan spins for about a second or two and then stops. Tried moving the sandbar to the 3-volt line and the auto lamp to the 5-volt line and nothing happened (fan didn't move at all).
I'd appreciate any insight into either of my problems -- how to get the non-ATX to deliver a solid 12 volts and/or how to get the ATX to run at all.