Which pins to short to test 24 pin power supply?

[VS Omega]

Hey all,

Just a really quick question - I know with the 20 pin ATX PSU's it's the green pin and the black pin shorted to make the PSU start without a motherboard. The PSU I need to test is 20 pin + 4 pin (the 4 pin slides into the module next to the 20 pin so the PSU can be used in older PCs), I tried the normal 2 green pins but it won't switch on - just wanted to be sure the PSU is dead and I'm not just shorting out the wrong pins.

The motherboard LED comes on but the power button wouldn't turn the PC on - I tried shorting the motherboard power switch pins and it didn't work. Before the computer not starting at all it would take a few times pressing the button before it would actually switch on. I calculated that I needed an 800w PSU for my OC'd Quad Core + 4 HDD's so I strongly get the feeling it's the PSU but just wanted to be sure.

Thanks

Bonus question - will running too many components on an underpowered PSU eventually damage it?

[holdensupporter2005]

I don't short any pins, I went out and bought a PSU tester. It has about 10 LED's which checks the different voltages on different wires. They are fairly cheap if you are testing many PSU's. Recently I have found that in some instances a dead CMOS battery can cause the same effect as having a faulty PSU. Try taking the CMOS battery out of the motherboard and waiting about 20 minutes and then try powering the PC up.

My PSU tester is similiar to this one except black not blue.

[VS Omega]

I'll do the definitive test to see if it's the PSU - put it in this PC and see what happens. Don't need a tester because I'm not into all that computer stuff any more... thanks for your response anyway

[tommo82]

. I calculated that I needed an 800w PSU for my OC'd Quad Core + 4 HDD's so I strongly get the feeling it's the PSU but just wanted to be sure.

How did you calculate it?

800W is alot of power - almost unheard of for a consumer PC (even if overclocked) to consume that.

[VS Omega]

4 hard drives, 2 dvd burners, 4gb overclocked ram, quad core q6600 pushed to 3.4Ghz, 7+ USB devices, 4 LED fans, TV tuner card, network card, overclocked 7900gs.. it came up to like 783w or something, rounded to 800w to be safe.

If I run the computer at stock speeds it'll sip ~480w.

BTW tested PSU in other box, it's dead so I'll get a new one tomorrow or the day after

Adding to this: In the interest of saving making a new thread how do these nVIDIA 9500's compare to the 7900gs? They're only like $100, if it's better then that'd be awesome, should upgrade.. if not then