More booting problems

[MakBrandon]

The other day my computer stopped working out of the blue. Yes, its a custom built system and had been working great for over a year until this.

The issue: After coming home from work one day, I noticed my computer was not on as I had left it. I tried to power up but nothing happened when I clicked the power button. I mean NOTHING. No beeps, no lights flashing, nothing. I checked the power cord, the outlet, the switch on the psu and everything seemed to be in good working condition.

Specs:

Asus M2N32-Sli Deluxe Motherboard (Wireless Edition)
Apevia Thermally Advantaged Case
AMD Dual-Core Processor 5200+ @ 2.6GHz
4GB Crucial Ballistix Ram PC2-6400
XFX NVidia GeForce 8600GTS 730Mhz 256MB PCI Express x16 Video Card
500GB Seagate Barracuda SATA II Hard Drive 16MB Cache
750GB Western Digital Caviar SATA II Hard Drive
LiteOn 20x DVD-RW DL SATA Burner

I ran through a few check lists to no avail. I manually checked the powersupply with a multimeter to ensure correct voltages and everything seemed nominal. I tried clearing the CMOS, only booting with one stick of ram, unplugging and replugging all of the connections and still i had nothing. I checked the power button with the multimeter to make sure it was shorting the leads together and it was. The light on the MB does come on when the psu is connected and the switch is on so i know the MB is getting power. Can anyone think of anything else I should try before investing in a new MB?

 

[jsc]

Are you using the PSU that came in the Apevia case? If so, that is probably your problem, not the motherboard.

Try to verify (as well as you can) that the PSU works. If you have a multimeter, you can do a rough checkout of a PSU using the "paper clip trick". You plug the bare PSU into the wall. Insert a paper clip into the green wire pin and one of the black wire pins beside it. That's how the case power switch works. It applies a ground to the green wire. Turn on the PSU and the fan should spin up. If it doesn't, the PSU is dead. If you have a multimeter, you can check all the outputs. Yellow wires should be 12 volts, red 5 volts, orange 3.3 volts, blue wire -12 volts, purple wire is the 5 volt standby. The gray wire is really important. It sends a control signal called something like "PowerOK" from the PSU to the motherboard. It should go from 0 volts to about 5 volts within a half second of pressing the case power switch. If you do not have this signal, your computer will not boot. The tolerances should be +/- 5%. If not, the PSU is bad.

Unfortunately (yes, there's a "gotcha"), passing all the above does not mean that the PSU is good. It's not being tested under any kind of load.

Motherboard LED also does not mean much. It is powered from a small separate section of the PSU, not the main output.

Try to borrow a known good power supply.

 

[MakBrandon]

Thanks for the speedy reply. I did the paper clip trick when i was testing the psu with a multi meter and all of the voltages were correct within the tolerance. However, the grey wire didn't seem to be functioning as you said. Yes, I can try and find another PSU to try so I guess thats what I'll be doing next.

 

[MakBrandon]

Also, the power supply did not come with the case. It is a Sunbeam Nuuo 550W power supply.