I have a power supply (it's sold as 400W but rated at 305W) which has a 20-pin connector. The motherboard has a 24-pin socket. Since the 20-pin plug fitted in the 24-pin socket, I hoped it would work. The (new) system worked fine for a few days, then the PSU stopped working. I'm wondering if it was because the PSU was cheap, or the computer was drawing too much current, or if it was anything to do with the wrong number of pins on the connector? (Reading the sticky, I'm glad it didn't explode ) Asus M2N / Athlon64 X2 3800 dual core + Slackware
Well, having a PSU rated for 305W and sold as a 400W is like having a car sold with a V8, but only giving you a V6. While it's usually not required to have a 24-pin (the connectors are keyed to make it extremely difficult to plug it in wrong) power supply, the reason for the shift from 20- to 24-pin units is due to a shift to the +12V rail. My guess is that's where your power supply is not up to snuff. What little it had wasn't able to keep up. Or, it could've just been time to go. Having said that, I do try to run a 24-pin when I have a 24-pin board, but, except for my DFI LanParty board, the others I have aren't as picky. In any case, if you can swing it, get a Corsair or OCZ unit. Anything above 500W will be safe for all but the most extreme rigs. If those are too rich, FSP group (FSP, Fortron, Sparkle brands) and Ultra brands sporting 500-550W (or more, if you like) should also do the job.
There is an LED on the motherboard that stays on even when the machine won't boot. Is that probably due to the PSU providing enough current for the LED but not to boot the computer, or might the fault be on the motherboard? (The LED doesn't noticably flicker when I press the power button)
The LED provides an indication that there is power to the board, regardless of the system being turned on. The reason is just to remind you that there is power, and that you should switch off the PSU or unplug it before swapping parts. My recommendation is look at a new power supply, as what you have now doesn't seem to be trustworthy from what you've provided regarding the ratings. A good unit isn't dirt cheap, but it's well worth the money. For budget purposes, I'd look at an FSP or Ultra 500W or better unit, and if you can swing it, Corsair or OCZ.
