I’m building a PC to use as a fileserver. I’ve assembled my components and everything seems cool. I hook up the CPU, the memory sticks, the vid card, do all the little power on/speaker/led jumper connnects, etc. Hook it up to the PSU, get my Linux install disc ready, press the power button and…nothing. Zero, zip, nada. The PSU doesn’t come on (a brief blip of power passes to the mobo; I can tell because the network jack lights up for a split second), but that’s it.
So I start testing stuff. I haul out an old Pentium III, hook up various components to it. PSU checks out. So does the case’s power switch. OK, I figger, must be a bum mobo. Hello Newegg, please send me another.
So I get the new mobo. Go through the same exercise. Hit the power switch and…AGAIN, NOTHING.
At this point I’m tearing what little hair I have left out. I figure the odds on having the exact same problem with two completely different mobos by two different manufacturers are pretty slim, so I’m guessing the problem here is something I’ve done. But I have no idea what.
This isn’t the first PC I’ve built, FTR, and also yes, I’ve checked the connections to be sure they’re tight, and yes, the PSU is plugged in.
A long shot, but… Are the right 4-pin power connecters being used? Power supplies often split the 24-pin power connector into separate 20-pin and 4-pin connectors, but there’s usually a separate 4-pin connector as well and you don’t want to get them mixed up.
It’s the right connector…this mobo has them in separate spots, so I had to unclip the 4-pin connector from the 20 pin. In fact, I had to cut a little of the heatshrink holding the 20-pin and 4-pin cable together to successfully hook them up – the new mobo has them spaced pretty far apart.
(Edit: Never mind, was misremembering something. I’d verify what that separate 4-pin connector is for though; you might not need it and that might not be the right plug from the ATX connector.)
I’m 99% certain Fugitive is right. I found a FAQ on the Antec site that stated that the wiring for the single 4-pin connector and the 4-pin extension on the 20+4 connector is not the same. If your motherboard’s main power connection is not 24 pin, you should not use the 4-pin extension you detached from the main 20-pin connector.
No link, because the FAQ was in some weird pop-up, but if you go to Antec’s site you should find it.
EDIT: Oops, Fugitive pulled his original post. Anyway, the two types of 4-pin adapters are not interchangeable, at least on Antec systems.
The connector from the Antec power supply is 24 pins, but you can remove the 4-pin side for mobos that have them in separate locations (like this one).
At any rate, there are no other 4-pin connectors on this PSU (other than plain ol’ molex connections), and the 4-pin I’m using plus the 20-pin are the only ones “hard wired” into the PSU (the rest are modular), so I’m pretty sure it’s the right one.
Besides, I’d think the PSU would at least power up upon receiving the go signal from the mobo, even if the 4-pin wasn’t connected at all.
Argh, I was looking at an older power supply manual and was probably right to begin with. :P
Those 4-pin plugs attached to the ATX plug are removable just so they can be used in 20-pin motherboards; those 4 pins aren’t meant to be used anywhere else. If the power supply doesn’t have a separate 4-pin connector (usually called something like “12V CPU Power”), you may need a new power supply.
The pinouts are definitely different – the separate 4-pin connector is two 12V lines and two grounds, while the 4-pin connected to the ATX plug is a combination of 5V and 12V and no grounds. Unfortunately they didn’t make their connectors incompatible…
I’m downloading the motherboard manual now to verify, but their web site is painfully slow.
(Edit: Exactly which model of power supply is it? My Antec TruePower 480 has a separate 4-pin 12V plug.)
OK, I’m an idiot, you’re right, there is another 4-pin (cleverly disguised as an 8-pin that you can split in two for dual procs), and it is 12V, which is what the mobo manual says to use.
However, it still isn’t powering up.
Any chance I killed the mobo by using the wrong pins? I’d be surprised, since the thing hasn’t powered up at all.
Heh, if it makes you feel any better I wouldn’t have expected or noticed that right away either.
Unfortunately, it’s certainly possible the board (or even CPU? I’m not sure) is damaged. The only reason I even thought of this was from recently reading a thread where someone had fried his motherboard by mixing up those connectors… The only way to be sure would be to retry on a new board.
