[HELP] Front chassis fans not spinning

yonibz

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Apr 29, 2011
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Hi,

The two front chassis fans do not spin. I found this out since my PC shut down with a CPU overheating warning. I have always had problems with these; either the speed readings are off, or they sometimes spin, or only one spins...

I have these ones which are temperature controlled:
Fans

I put the temperature sensors on top of a heatsink so they are always at a high power, but they never seem to be spinning fast, even when they do work. If i stop the already slow fan, it doesn't pick up again and spin, it simply stops.

This is my mobo: Motherboard

Could the fans/temperature sensors be faulty, or could there not be enough power going to them? I have a 500W PSU powering the following:
AMD FX 8350
Sapphire AMD RX480 8gb
8GB RAM
PSU - Aerocool 500W

EDIT: : Here's a video with the BIOS readings

I'm tempted to buy new case fans, thinking they could both be faulty, but it does seem like theres not enough power going to them.
 

GorfTheFrog

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Aug 12, 2009
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Hi -
So, a quick google of "PSU sizer" pops up several websites that allow you to enter your configuration in order to get a recommendation on ... PSU size!

From a couple of sites, yes, it does appear that you may be under-powered. However, I think you'd expect to see other problems besides a couple of fans not running.

Do you have the fans plugged into the MOBO or are they running directly from the PSU? Do you have another machine you can use to swap out parts and test whether it is the fans themselves or the incoming current? What if you only connect 1 fan? I'd try to narrow the problem down, but you probably do need a stronger PSU.

Also ... maybe someone with more experience can chime into this thread.

Good luck!

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yonibz

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Apr 29, 2011
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Thanks for replying so fast, and doing some research for me!
The fans are 3 pin, plugged into a 4 pin mobo connection. I haven't got another machine i can try unfortunately, so i have tried to narrow the problem down by unplugging one of them, to see if the other works. On start up, it manages to gather some power to spin, but it is VERY slow, and if i stop the fan, it just gives up completely.

I'm really not sure whether it is a fan problem or PSU, because the rear exhaust fan, which came with the case seems to work.
 

yonibz

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There doesn't seem to be an option to do this. Perhaps i'm missing something, but i can't set the voltages in the bios, and the fans are temperature controlled and only 3 pin.
 

GorfTheFrog

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It is strange that the fan gives up completely if you stop it manually. Then again, I feel like I've seen fan power connectors start at "full power" and then throttle back after booting.

I guess if it were me, I'd try to plug one of the front fans into the power for the rear exhaust fan, and vice-versa. I'd also try to plug the fan directly into the PSU. A couple of fan cables for troubleshooting are way less expensive than a new PSU.

One other thought, have you checked the Windows power settings and the bios to see if there are any settings controlling how the PC is optimized? This is usually more of a deal on laptops where you can optimize for longer battery (reduced CPU speed) or aggressive cooling. Usually not an issue with desktops, but it would be something else to check.

Good luck!

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yonibz

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I will try to swap a rear and front fan to see whether there is any change. How do i go about plugging the fan into the PSU? Surely i need an adapter that turns 3 pin into a connector?

Checked power settings, and all are set to high performance. I checked the power requirements of my build but my 500w seems more than sufficient...
 

yonibz

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There doesn't seem to be an option to change the voltages in my bios. All i have is the option to monitor them (enable/disabled monitoring), and enabling/disabling Q Fan control.

I checked bios and these were the readings being shown in the video below.

Video showing BIOS readings
 


I'm talking about measuring voltages using a voltmeter at the fan's power connector. BIOS voltage readings are meaningless for this situation.