PC won't start. Power supply buzzes then stops.

PC built from parts has been working fine and today wont' start up.

The power supply box buzzes then turns off. There is a very slight buzzing but nothing else happens.

There has been nothing done to the pc.

It has had a new Nvidia 660 Graphics card recently installed, 8gb RAM, ASUS Motherboard P8Z77VLK, 850 watt cool power. Win7 OS

Any advice would be much appreciated. At a complete loss as to what to check first.

 

Some troubleshooting steps:
1.you can test the system with a known good power supply
2.Some Power Supplies these days have a built in self tester, to see if the Unit is still sending and receiving power
3.Disconnect all internal and external peripherals, and restart the computer. If the computer boots, add the peripheral cards back one by one until you find the bad one.
If the problem persists, the system board is probably bad
4.you can also test with known good power cables or wall outlets


also is there any activity coming from the power button at all, if so what color. By the way when you say the PC wont start do you mean not power, POST, or boot? If it can POST and if your bios has a diagnostic utility please run it and post the results.

 

Thanks so much for this reply. I am trying the peripherals suggestion.
How would I know if the power supply has a built in tester?
Also, the power button lights up blue for a second and then it goes off.
It doesn't allow me to do anything after it turns off. I don't think it can POST and I don't think it has a BIOS diagnostic utility (but am not sure).
Thanks again. I'll repost when we've tried all the peripherals.

 

Tried without all peripherals. Tried new power supply cord. Still not working.
It just happened suddenly. Was working last night but wont' work today.
New cord seems to only give a slightly longer buzz when turned on but it turns off straight away.
Big thanks for your help.

 

if the PSU does have a tester on it there will be a small LED light on the PSU with a small black button next to it

 

Unfortunately it looks like there is no tester on the psu.
Thanks

 

With new power supply cord, it is now buzzing every few seconds and the cpu and 2nd fan try to spin but just stop and the top fan rotates at the start then stops.
Still won't turn on.
Thanks

 

With all peripherals tested and no problems found, it definitely sounds like the issue may very well be with the power supply, especially with the change in buzzing when power cord was switched. Doesn't seem like its outputting the power required from the system, and the buzzing me be from a blown capacitor or the fan in the power supply.

 

That definitely sounds like it.

Can I ask whether, when you say: "Doesn't seem like its outputting the power required from the system, and the buzzing me be from a blown capacitor or the fan in the power supply." does this mean that the power supply isn't up for the job or how could it have broken overnight?

Also, do you know if the only option is to replace the power supply or should I take it to someone and find out if it's a blown capacitor or the fan in the power supply? I haven't got a spare to test with.

I think the fan might be the issue as that is where the whirring/buzzing is coming from and when powered on, it turns and then stops.

The PC has been working fine for about 2 months with only a new graphics card inserted a month ago. It was fine last night.

Do you know what could have done this to the power supply?

Really appreciate your help with this.

 

Greetings, goweb...

I agree with djdmoney863 - this does look like a power supply problem. If the PSU was getting no control from the motherboard you probably wouldn't hear any buzzing noise.

Power supplies do just 'go bad', but incoming voltage fluctuations/spikes are the usual culprits - is the machine connected to a surge suppressor or UPS unit?

Unfortunately you must load a power supply in order to test it, but the catch-22 is that if the PSU is faulty any components connected to it could also suffer damage while testing. Unless it's an obvious fan problem the safest route would be to uninstall the PSU and take it to a reputable repair shop to have it checked out.