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CPU fan not working? Ideas?

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  • CPUs
  • Motherboards
  • Product
Last response: in CPUs
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September 2, 2008 3:22:14 PM

I just put together a new system with a Q9650 CPU on a Gigabyte EP45-Extreme motherboard. I have a 720W Enermax Infiniti modular PS and a ATI Radeon 4870 GPU. Everything is powering up except the CPU fan.

Anyone have any ideas that can help me out? The fan and heatsink is the standard one that comes with the CPU (for now).

Thanks in advance.

PS. Please don't flame, this it the first system I've built in years so a lot of this is new to me.

More about : cpu fan working ideas

a b à CPUs
September 2, 2008 3:42:03 PM

most likely its a bad fan......connect the fan to a 12V battery and see if it spins.
or, u could get a voltmeter and check if there is a 12V voltage across the connecting pins on ur mobo where u plug in ur fan

btw.....i would recommend not to turn on ur pc till u fix the issue
a b V Motherboard
September 2, 2008 3:45:53 PM

Check to make sure the Fan is plugged in to the CPU header on the motherboard (sounds asinine, but I've seen it). The other option is to buy an aftermarket cooler for it (could be a bad fan)
some examples, depending on case depth.

http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$25 Arctic Cooling Freezer 7 Pro
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$50 Zalman 9300AT
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$60 Zerotherm Nirvana
http://www.newegg.com/Product/Product.aspx?Item=N82E168...
$50 Tuniq Tower 120 (Swap out the fan for one with higher CFM if you want it cooler)
http://www.frozencpu.com/products/6913/cpu-noc-04/Noctu...
$70 Noctua NH-U12P (cools my 9850 with no issues)(Swap out the fan for one with higher CFM if you want it cooler)
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September 2, 2008 4:20:56 PM

Thanks for the quick reply. It's pretty dissapointing if it turns out to be a bad fan. Or worse, the mobo! I just bought the parts yesterday. :) 

sarwar_r87: Unfortunately, I've already tried to boot the system. When I noticed the fan wasn't spinning, I turned off the power.

IH8U: yes, it's connected to the correct header. I was pretty paranoid about that so I checked and rechecked. I think I may have to run out and buy a new fan today since I wanted a better one in case I tried to OC at a later date anyways.
a b à CPUs
a b V Motherboard
September 2, 2008 4:32:41 PM

Try spinning the fan to see if it comes on.
Then you can go in the bios and set the fan to spin at all times, not just when a temperature is reached.
September 3, 2008 12:20:33 AM

I took the fan into the shop where I bought it and the tech tested it. It works. Now I've taken everything apart and put it all back again to make sure I didn't miss anything and it still won't come on. The system boots up but shuts off after a few seconds. I think I might take the whole thing into the shop tomorrow to have them look at it because this is beyond my abilities I think.
September 3, 2008 12:30:41 AM

If the system didn't power itself off when you noticed the fan wasn't spinning then that means that the cpu didn't get hot enough for the bios to turn off the system. How long was the system on before you turned it off? was it posting and everything ok?

if you have fan control on in the bios then it wont start the fan up until it reaches a certin temperature. You can turn this feature off in the bios but probably the cpu just hasn't gotten hot enough for the bios to kick the fan on.

That being said i would try to load the bios and quickly check the cpu temp. If it is really high then i would quickly power off the system. better to be safe then sorry
September 3, 2008 1:44:02 AM

If you don't like the hassle, just get an aftermarket fan/heatsink that has both motherboard power connector and 4 pin molex power connector. This way, you can connect it to the psu's molex connector, and get power directly, instead of going through the motherboard. Even if the mobo isn't sending power, it doesn't matter.

The Zerotherm Nirvana that IH8U linked earlier is like this. It even has a fan speed controller so you can change speed when connected through molex.
September 3, 2008 4:39:00 AM

As others said, just get an aftermarket cooler with the proper adapter for molex/3pin. You dont want to go through the hassle of having to return your motherboard and disassemble/reassemble the entire system for a dead cpu PWM header.
September 3, 2008 1:27:44 PM

Yeah, I was looking for an aftermarket fan but they are all so HUGE! Even the guy in the tech shop was iffy on whether some of them would fit or not because the motherboard has some built in piping and a huge heatsink for the pipes. And I can't return a fan once it's been opened so I can't really get one until I'm 100% that it will fit.

kyeana: The system will only power on for a few seconds and then turn off so I can't even get into the bios. I'm going over to my brother's place this morning to see if he can offer any suggestions as well, maybe I keep missing something...

However, I think the issue might be the motherboard not providing power to the connector. If we can't resolve the issue, the shop will have to replace this mobo for me of course.

Thank you all for you suggestions, I'll let you know how it goes.
September 3, 2008 11:01:58 PM

Found the problem. Turns out it was the video card trying to draw all the power. The ATI Radeon HD 4870 has two power inputs which I hooked up daisy-chain style to the front and rear fan. When I plugged the two outlets directly to two seperate leads (for PCI-E) on the modular PSU every was up and running.

Hope I made this clear...

Thanks everyone for your suggestions and help!
!