CPU fan spins for a second and immediately spins down

[twosquares]

I'm in the process of building a new system, and this problem is really stressing me out. It has never booted, and there's nothing installed on the hard drive. My motherboard has a CPU, CPU cooler, speaker, and PSU plugged in. The power supply passes the paper clip test, but it could still be faulty somehow. My motherboard is outside of its case on a piece of cardboard. I have tried different materials like printer paper, glass and wood, so I don't think the motherboard is shorting out.

When I turn the pc on (with the motherboard pins and from the case button), the fan spins for a fraction of a second and immediately powers off. The motherboard lights turn on for the same amount of time. The power isn't on long enough for the speaker to beep. The same thing happens when I add a stick of ram and a graphics card. I have cleared the CMOS without any success.

If I try to turn the pc on again, nothing happens at all. The PSU has to be switched off and on again to get the fan to spin again. I'm thinking that there is something wrong the CPU or the cooler. I have removed and reattached the cooler several times. It has the stock thermal paste on it. I guess the CPU could be overheating, but I doubt that it could in a fraction of a second. I took off the cpu fan (still plugged in) and put my finger on the CPU. There wasn't any notable temperature change.

Thanks so much for the help!

Specs:
CPU: AMD FX 8350
Cooler: Stock AMD cooler
Motherboard: MSI 970 Gaming
Graphics Card: Gigabyte G1 GTX 970 Gaming
RAM: Crucial Ballistix Sport 8GB (1 x 8GB)
PSU: EVGA 500W Power Supply
HDD: Western Digital Blue 1TB 7200RPM

 

[Andrew1337]

Try to unplug your Power supply 24 pin connector and plug it again to the motherboard, but put some pressure on it when you do it.

P.S if that doesn't work make sure that you plugged every motherboard connector really tightly. But do not put extreme amount of pressure to the motherboard because you can break it.

 

[twosquares]

I removed the 24 pin connector and the 8 pin cpu connector and plugged them back in. The same thing still happens. Could there be a problem with the powersupply or my CPU?

 

[Andrew1337]

It's mainly of a power supply. Try to swap another power supply to the system and look if that works.

You can try to change power supply cord to diffrent outlet on your wall.

 

[tsnor]

Assume this is what you've done based on your post:

You have no memory on the MB, the video card is not installed, the drive is not connected by either the sata cable or the power connector.

You've remove the case front panel connectors from the MB. No audio, no power switch, no usb, etc.

Then you momentarily shorted the power on switch pins on your MB. The CPU fan turns on for a second then shuts down.

Steps:

1. Verify CPU fan is plugged into CPU fan header and not some other fan header. Many MBs will immediately shut down if they cannot see the CPU fan spinning via the cpu fan header connector.

2. Follow jumper procedure to reset BIOS.

3. Verify your MB level of the BIOS is modern enough to support the FX 8350 if this is an older board. Unlikely this is the problem, so don't go crazy trying to figure out the BIOS level on the MB.

4. As Andrew says above, Swap PSU if you can. It's either the MB, PSU, CPU at this point. If a new PSU doesn't get it working RMA the motherboard. It's rarely the CPU.

 

[Isokolon]

does the fan really spin? does it actually loop 2 times?
could be a broken fan as well if it doesn't. but it's easy to verify.