Power Supply Acting Weird

[jey18]

Got my old computer running a while ago, unfortunately the PSU I was using couldn't sufficiently power my graphics card so I could only do mundane tasks such as IM, and browse the web. It's a decent computer:

MOBO: MSI K8N Neo2 Platinum
CPU: AMD Athlon 64 4000+
Graphics: BFG nVidia 7600GS 512MB
Memory: 2gigs Kingston Value? PC-3200
Hard-Drive: Hitachi Deskstar 60GB IDE

Anyways I got a new power-supply, which I know is in working condition because I just pulled it out of my brothers computer he rarely uses (which runs games just fine with his Sapphire 1950 something or other GPU.) I remove my old PSU, install the "new one" and hit power.... nothin' happens.

I put the old one back in, starts right up. So I tested the new PSU to make sure it works (which like I said... it does) and it fires up when I complete the loop (ie: run wires from green->black.)

So I'm kind of dumbfounded why it won't start the computer but the old PSU will?

The "PSU" is a TTGI TT-520SS which I have no idea where I got it from, I put it in my brothers computer 2 years ago. I double checked all the little power connectors from the MOBO to the case, which work fine with the old one...

I'm stumped.

 

[roadrunner197069]

Prolly forgot the cpu 4 pin and then remembered it when you went back.

 

[jey18]

Nope. Double checked everything. Right now I'm running both to power the computer... got to windows.

I would rather prefer using just the one... any other ideas?

 

[Shadow703793]

Bad power switch?

 

[ZOldDude]

Some PSU's and MB's don't always "talk" to each other correctly.
At boot time the PSU's preset "good PWR ON state" may not be detected in time.

Try holding in the PWR button on the computer for a full sec and see if the system boots.

 

[jey18]

Tried it, still no luck.

 

[hotdogmichigan]

Once heard stories that some psu could be incompatible with some motherboards (like using a 24 pin psu with a 20 pin mobo) because the psu had switched some wires. Maybe someone else has more precise information.

This is no solution but I just wanted to share it to you.