...somethin wrong here... am I missing something here?

[x88x]

Hmm, I wonder...that would make sense...I'll try that when I get home.

[x88x]

Hmmm, still doing it. I checked both of my nice spare PSUs, and they both do it too, so I think I'm missing something. I tried putting a load (hefty DC motor) on the 12V line, and that didn't change anything except for making the voltage go down, just like it's supposed to. Using the PSU I want to convert as a sample case, the 12V line puts out 7.40V, the 5V line puts out 2.93V, and the 3.3V line puts out 2.52V.

[billygoat333]

have you tried a different power cord to the PSU? just an idea...

[x88x]

No, but the same power cord used with an external adapter gives the correct voltages. I'm thinking it must be something weird with the PSUs that I'm missing.

[mDust]

I'm thinking it must be something weird with the PSUs that I'm missing.

Have you tried hooking it up to a motherboard and testing the voltages with it running? It may be expecting some of those 24pin connector circuits to be closed. Since you're probably just grounding the green wire it's turning on, but is smart enough to not provide full power unless it has somewhere useful to go.

[x88x]

Hmm, no, I haven't tried that yet...I'll try hooking one up when I get home tonight.

[diluzio91]

That sounds familiar somehow... a failsafe incase something get plugged in wrong?

[x88x]

Hmm, ok, here's something interesting..
Going off this pinout, +5 VDC Standby Voltage rail is outputting the correct 5V. I tried crossing it with ground and 'Power Ok', and neither did anything. Also, 'Power Ok' doesn't show any voltage, so from those two, I'm guessing that the PSU is in standby....now I just have to figure out how to get it out of standby...

[x88x]

Ok, after I finally researched this.. ..I discovered that, yes, most new PSUs need a load on them in order for them to actually power on. It turns out this is usually handled by hooking a 10 Ohm, 10W resistor between the 5V line and ground. I've verified this with two pretty hefty 12V electric motors that I have lying around. With one hooked into the 12V line, it barely turns over, then when I hook the other into the 5V line, suddenly the first bursts to life. Now I just have to get my hands on a 10 Ohm 10A resistor... The best I have right now are some 120 Ohm 3W resistors...and I only have 6 of them, not the 12 I would need to get down to 10 Ohm. I tried with the 6 I have, and it does have a noticeable effect on the motor, but not enough to bring it up to 12V.

[billygoat333]

eh. probably just needed to sacrifice some goats to the gods of powahh. (and by goats, I dont mean me... )