Hi, I have a few generic PSUs hanging around and I was thinking of changing one of them into a testbed for fans, cathodes etc. What sort of load is required for the PSUs to function and on what rails? Also, what will happen if I don't meet the load requirements? If it needs a load on the 12v rail that's fine but if it requires one on 5v or 3.3v i'll have to stick a resistor on it. Thanks.
Specification usually says minimum 2-4 A load on 5V or 3.3V, but not many suplies actually need that, you would probably get 0.1V och 0.2V more on the 12V rail during high load if you load 5V or 3.3V properly. Above is results of my personal testing, i do not guarantee accuracy for your supplies.
The supply is expendable anyway; I'll just stick a few high wattage resistors on the side of the PSU case with thermal adhesive and let the fan cool them. Thanks for the figures
I just did this with one of my old 450w supplies. Put a 5 ohm, 25 watt resistor on the 5v line, and seems to work pretty good. Read this thread (which is what I did) to get started http://forums.bit-tech.net/showthread.php?t=82375
Thanks a lot, that should be really helpful There's also a link in that thread to a page I've been looking for for a while now, so that clears that up as well
As well as the other stuff (4mm posts for different voltages, rocker switches etc) I got two of these, 4.7ohm 25-watt (they look great). If the current draw isn't high enough - it's an uber-cheap 350W supply - I can just add another in parallel to make it higher. Time to get Dremelling Thanks for all the help, everyone
Those are exactly the same kind I put in mine. I got 8 of them off ebay for about $5. I ended up attaching it to part of the PSU chassis (for additional heatsink) and it still put off some pretty good heat. Should run quite a bit cooler with it all buttoned up and the fan on though. Also bought a dark green clear plexi top to "spice" it up a bit...should be pretty nice when all done
