Why do I keep having Power Supply Issues?

Question

I have a computer that I built January of '06, and until two weeks ago I have never had problems with it. Then, the power supply started giving off this burnt smell as if it was on fire and the computer would shut off. My computer is NOT overclocked and runs its hottest at 55C during high loads.

I remedied this by purchasing a new power supply, and that worked fine for the last two weeks, until today when it has just stopped working completly.

The difference between the power supplies that might be a factor is that the old one is 550W, and the new one is 400W as that is all I could get locally. Perhaps I melted that PSU.

Well I am using the one that smells like its burning to write this, so the computer works fine and it is the PSU. What can I do to prevent this in the future?

Main System Components:

Intel Pentium 4, Socket 775, 560, 3.60 GHz, 1MB Cache
Intel D925XCV Desktop Motherboard
ATI Radeon X700 Pro 256 MB Video Card, PCI-E
2 GB RAM

I built it myself, and the PSU I gave it was overkill. It did not "come" with that PSU.

Also the computer runs at highest 55C so its not overheating, I have a Zalman on the CPU and 4 fans in the case plus the one on the video card. I just don't get why the PSU's keep dying.

Answer 1

You never want to replace a power supply with a lesser wattage than the one it came with. As you've noticed ;-) Maybe try one higher than 550. Does your graphic card have it's own fan? Is it working? You can also buy these little fans that you just stick inside to help keep the heat down... good luck.. :-)

Answer 2

Try getting a psu that is higher in amps on the +12 volt side. There are some that run 37 amps. Look at and compare the two that you've burned up. Check the amps from the faceplates on each under the +12 volt column, look at the amps. The 550 watt may or may not have more amps than the 400 watt did. Try ordering from tigerdirect.com by phone, the techs there will help you find what you need.

http://www.tigerdirect.com/