Bad Power Supply

[AuroEdge]

I have a MicroATX power supply. I've been having stability issues with a PC I'm repairing so I've replaced every component I could think that would cause issues. Having switched to a new motherboard, different cpus, and different ram modules I still experience bad Memory Tests and random lockups. I have a 400W PSU for this motherboard: http://www.centrix-intl.com/details.asp?productid=3841. That should be plenty. The power supply looks fine from the outside. It's not my computer so I can't say for certain the common signs of failure e.g. smoke, smell, or excessive heat have ever occurred.

If I do need a new one, what would be an average power unit to buy?

[Nelson37]

Such instability is a common sign of power supply failure, they rarely if ever show any external signs. Anything that fits in the case with similar power would be fine.

Then you should put back all the original parts, and either return or eat all the probably unneeded parts you got. While you're at it, get a second power supply for testing in the future, this would save much wasted time, effort, and cash.

That board bears a striking resemblance to several dead E-machine boards I have in my shop, I would recommend using a better quality of replacement parts.

[Bjs]

Well 400watts is common and more than enough for the system ... but if there's even the tiniest fault it can cause system stability issues

Repair ... for what reason ?

Other parts considered for possible replacement

1: Case ... buttons can be faulty in aging cases
2: Data cables ... eventually develop inconsistencies
3: Graphics card ... even small faults can trigger system freeze due to agp and usb sub system
4: Drive ... as they wear out problems such as freezing, sudden restarts, ect, develop

Memory tests ... or bench marking utilities ... bin most of the buggers ... Ive seen memtest report in error on systems with no problems

Have a tweak in the bios's memory settings ... if that board allows for adjustment then lower the mhz / volts

Bench testing components out side of the case is the normal approach for problematic systems for the purpose of locating the fault

[jman98]

I've seen power supplies cause really weird problems when they seem to be OK as far as you can tell. I had an issue a few years ago where my boot drive seemed to be horribly corrupted, perhaps beyond the point of recovery. I was getting power to the PC, but the boot drive would not boot at all. Where I live we have power outages sometimes in heavy rain (I know it's weird, but it happens) and I remembered that my PC was left on while I was at work and when I came home I saw the telltale signs of a power outage in my house. I've had power outages ruin power supplies, so on a hunch I replaced my power supply and my PC booted fine. Never had another problem with that drive. In fact, it still works fine. So yes, I think there is a possibility that replacing your power supply may fix your problem. As far as what power supply you need, that depends on what exactly (you haven't said) you have connected to the motherboard. If you have a lot of devices attached, especially one of those newer power hungry graphics cards, 400W may be inadequate.

[AuroEdge]

It has an AMD Athlon T-Bird 1.3GHz, 1GB PC100 RAM, and an nVidia GeForce 2 MX400. Nothing outrageously power hungry. I have to double check but I think the CPU is actually the power saving variant of its speed.

Testing the components elsewhere would've been the cheaper non lazy alternative to buying new parts. Having swapped out every part besides the PSU seems the likely cause. This was something I have no experience with.

EDIT: It might be an issue with the capacitors on GT133KT motherboards. Not so much they're defective but the fact that they don't exactly store a gratuitous surplus of power. Duron 750MHz is doing fine whereas the Athlon 1.3GHz is not. I will need to try the Athlon 1.0GHz I have lying around and see how it performs. Apparently the 0.1V jump from Duron to Athlon is too much to handle.