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

[nevermind1534]

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.

If you can wait, I'll add one of those resistors to my Digi-Key back order (they only cost a few cents, but there's one thing on there that won't be in until June or July.

[x88x]

Thanks for the offer, but I want to get this done asap.

[x88x]

...yeah, so much for ASAP. I finally got around to ordering some of the necessary resistors off Mouser on Saturday, shipped Tuesday, and I got them today.

I went ahead and picked up 10 because, hey, you never know, right?

and a single one:

I spent ~10 cents extra each (buying 10, these were $2 each) to get the kinda ones with heatsinks with mounts. That way I can just screw these onto the PSU housing or an old CPU heatsink or something, and keep it nice and cool. I'll do some testing to see how hot it gets. I'd rather just mount it to the PSU case, but I do have some old Pentium-era CPU HS/F's (you know, back when having a fan on your CPU meant you were serious business ) that I can throw it on if need be.

[altec]

You know you have problems when you can look at those resisters and say "Oh! Cool! I want some!"

I have no use for a 10W resister. Haha.

[x88x]

Well, I have no clue what I was doing wrong before..I must have been hooking something up wrong, because it wasn't working... Anyways, today I thought to pull apart my PSU tester to see how it was wired, and...basically exactly what the internet had told me.. 5A 15Ohm resistors on both the 5V and 3.3V lines. Apparently the 3.3V line load requirement is fairly new, but none of my PSUs worked with just the 5V line load.

So, the end result of that is that I finally have it working correctly! I ran it for a bit with some 12V 3A motors that I have acting as a constant load, and the 3.3V resistor seems to be just fine, but the 5V resistor got quite hot after just a short time. Looks like its time to dig through my box of old heatsinks! I knew I was holding onto those things for a reason.

[blaze15301]

hey if you want some smaller heat sinks let me know i have a few laying around id let you have.