Fans remain on when the system is shutdown

[Holy Popcorn]

I have just built a new computer and I am having an issue, when I shut down the computer the CPU, GPU and 1 of the case fans remain running, I have let it overnight and found the fans still spinning in the morning. The 1 case fans that's spinning is the only fan that's connected to the power supply the other 3 fans are connected to the motherboard and turn off as soon as the computer is shut down. When I turn the power supply off from the back, the fans will stop running and remain off when it is turned back on.

My specs are:
MB : Asus P8Z77-V
CPU: I5-3570K
PSU: AX-750
RAM: G.Skill F3-12800
SSD: Samsung 128GB 830 Series
GPU: Gigabyte GTX670
Case: Silverstone RV02-E

I'd appreciate any help you guys can provide.

[Stasis007]

Are you sure it's turning off and not going into sleep or hibernate mode? Should be a bios setting and/or check your power management settings in Windows.

[yurano]

The p8z77-v has a 'soft off' mode where its not completely off. The setting is somewhere in the BIOS I think.

[Holy Popcorn]

I don't think it's in soft-off mode, I held down the power button for 4 seconds which according to the manual should shut down the computer regardless. I couldn't find it in the bios though. And the power management is fine it's set to shut down.

[Stasis007]

Does your DVD/Blu-ray drive still have power after you shut down? i.e. will it open when you press the button?

Might be something in the Fan Xpert 2 settings, too. Maybe the offending fans are set to run at an unusually low temp?

[Holy Popcorn]

The dvd drive is off. If that is the case it makes no sense why the 3 fans are off when they are connected to the motherboard. My cpu is at 27C. And the top fan is connected directly to the power supply.

[Stasis007]

The dvd drive is off. If that is the case it makes no sense why the 3 fans are off when they are connected to the motherboard. My cpu is at 27C. And the top fan is connected directly to the power supply.

Well your motherboard has a bunch of fan headers all able to work independently. Something is happening to stop your PSU from powering down correctly, could either software or hardware related... I assume you've double checked all the power jumpers are in their correct place, including the case audio.

There were reports 2 months back that the GTX670 driver was causing shutdown issues, maybe double check you have the latest drivers.

Might pay to try a different PSU, if you have one available. Probably the biggest culprit after Bios/power settings.

[Xuvial]

How is it connected? Are you using a molex-to-3 pin fan connector?

It looks like this:

One of the big white ends goes to the PSU (the male one), the smaller one goes to the fan cable (sorry I know you're not stupid, but just check :P).

Re-check how the connectors, also try another fan...actually no, connect your DVD drive to it and see if the same power-on issue is happening. Your PSU could have a faulty 12v outlet.

[Holy Popcorn]

I disabled the cpu fan control in the bios and the issue remained so it's not a termperature matter. My driver is up to date, but I've formatted the computer to ensure nothing was causing a problem so I'm reinstalling the driver again just in case.

I think I may drop it by a repair shop, I don't have a different power supply and I've seen people on different forums suggest to check the power supply and motherboard.

---------- Post added 2012-07-24 at 03:06 PM ----------

@ Xuvial
Yea, it's connected correctly, I'll try to connect the dvd drive through the molex cable and see what happens.

But with that said, would that explain why the GPU and CPU fans are also on?

[Stasis007]

The case fan is running because the GPU and the CPU fan header are still drawing power. It's just running 'cos something else is causing the PSU to remain actively supplying juice.

Maybe try disconnecting the GTX670 as a last ditch attempt? Maybe it's faulty and pulling power through its auxiliary power connection. Plug the monitor into the motherboard.

Money's on a faulty PSU though.

[Holy Popcorn]

Yea it's not the graphics card I pulled that out, same problem.

[Holy Popcorn]

Just replying to say thanks for your help and you were right, I replaced the power supply and it worked fine.

[Xuvial]

Neat-o, glad to hear it