problem with antec power supply

[RumpMachine]

I've purchased two Antec 330W True Power power supplies (from Antec 660 Case) from Staples only to have the same problem with my system. I can start up my system with no problems, but when I restart it, sometimes it won't boot up. The hard drive shuts down (as indicated by the HD LED on the case) and the monitor does not recognize the computer. The boot up process comes to a halt, but the power is definitely on - the fans still run. When I am not able to restart, I have to wait about 5 minutes before being able to turn the computer back on (this never fails). The probability that my system is able to restart varies on a few factors:

1.) The more drives I power, the less likely I am able to restart.
2.) The longer I keep my computer on, the less likely I am able to restart.

I tried unplugging all of my drives and PCI cards with the same result. I tested my system with a friend's power supply (250w), and everything worked fine. I was able to restart with all of my drives plugged in, after the computer was on for an extended period of time.

At first, I thought that it was just a faulty power supply that I was shipped. Therefore, I ordered another one, but exactly the same problem occurred. Is there a problem with this line of power supplies? Are there compatability issues with my motherboard (MSI KT333 Ultra)?

Thanks in advance.

 

[AWEstun]

Well, since your friend's PS worked, and the new PS wouldn't work, it sounds like it's possible a motherboard problem.

What is/was the original PS brand? What it an antec, too? If so, maybe there's a compatibility problem between your MB and the antec brand of PS's.

Shelby