High pitched whine when rear case fan is plugged in.

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DarkJak

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Mar 15, 2017
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510
I've had this issue since I got the computer a few years ago, and mostly I've just done my best to ignore it, but I'm either going mad or it seems to be getting louder. I get a high pitched noise coming from my computer whenever the rear case fan is plugged into the 3 pin connector. It's not the fan itself, I've tried replacing it and still get the sound. If I stop the fan with a finger, I still get the sound. Only when I unplug the fan from the 3 pin connector does the sound stop. I fear I may have to replace my motherboard to fix this, but it's an intimidating task.

It's a Dell XPS 8700, all stock save for a new GPU, but the noise was around before that.
 
Solution
T
The settings would be somewhere in BIOS. The splitter you chose would work just fine.

It will not detect the fan on the splitter. If you're comfortable working with a crimper and pin remover, there is a way around it. Otherwise, you'll need to find the setting in BIOS.

If you're interested in the workaround, the basic idea is to pull the tachometer pin out of the connector, and put it in a second connector. You would have two 3-pin connectors attached to the 3-pin fan at this point. You then connect the tachometer to the 3-pin header, and the power/ground connector to the splitter.
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DarkJak

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Mar 15, 2017
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510
I plugged the case fan into the 4 pin CPU fan connector. The fan runs, and no high pitched noise. I've tried other fans on the 3 pin in the past, all had the same problem.
 
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the nerd 389

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Nov 20, 2012
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It's probably their implementation of speed control. It may be going bad on that header. Usually, they use a switching frequency of 22.5 kHz so humans can't hear it. It could drift to the ~12 kHz that you're hearing if a cap were to die in some designs.

The easiest solution is get a splitter and run it off of a different header. You could also get a fan controller.

For now, you could disable speed control for that header to fix it, but the fan would run at max speed. I don't know if the Dell XPS supports this, though.
 
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DarkJak

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Mar 15, 2017
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510
If my computer did support that setting, it would be in the BIOS menu, correct? I poked around in there and couldn't find it. As for a splitter, something like this would work, right? https://www.amazon.com/StarTech-com-12-Inch-Power-Splitter-Cable/dp/B005G3010U/ref=pd_sim_147_3?_encoding=UTF8&pd_rd_i=B005G3010U&pd_rd_r=TYFPWXD267MD9F6B270P&pd_rd_w=hBa8G&pd_rd_wg=TUWrg&psc=1&refRID=TYFPWXD267MD9F6B270P I have a 4 pin for the CPU fan and a 3 pin for the case fan. My only concern is that when I unplug the case fan from the 3 pin header I get an error letting me know that the fan has failed. Will it detect this fan in the splitter header, or will some configuring be required?

I should note that both headers are on the motherboard. The splitter mentions a PSU connector.
 
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the nerd 389

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Nov 20, 2012
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The settings would be somewhere in BIOS. The splitter you chose would work just fine.

It will not detect the fan on the splitter. If you're comfortable working with a crimper and pin remover, there is a way around it. Otherwise, you'll need to find the setting in BIOS.

If you're interested in the workaround, the basic idea is to pull the tachometer pin out of the connector, and put it in a second connector. You would have two 3-pin connectors attached to the 3-pin fan at this point. You then connect the tachometer to the 3-pin header, and the power/ground connector to the splitter.
 
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Solution
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DarkJak

Prominent
Mar 15, 2017
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0
510
I'm certainly going to try the workaround. I can salvage another connector from one of my spare fans. Do I need a crimper or will any old snips do? Finally, I'll have to purchase a pin remover. Is this what I'm looking for? https://www.amazon.com/Connector-Remover-Computer-Extractor-Sleeving/dp/B01G46DJVU/ref=sr_1_cc_9?s=aps&ie=UTF8&qid=1489618491&sr=1-9-catcorr&keywords=molex+pin+remover

I think I've answered this bit on my own. Wrong pin remover. For the fan leads it seems a staple does the trick. Going to buy a splitter and give it a go. Thanks for the help.

Edit: It seems that this workaround isnt going to work. When only plugging in the yellow lead I still get the fan failure error. I can still boot the computer, but it's an extra little annoyance.
 
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the nerd 389

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Nov 20, 2012
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The trick won't work if the fan isn't spinning. The tach signal tells the computer how fast the fan is turning, and if it's saying the fan isn't turning, it will trip the error.

The other benefit of this is that you can still read the fan speed as you did before.
 
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DarkJak

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Mar 15, 2017
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510
Good news and bad news. It works, no high pitched noise, no error on boot. The 3 pin header definitely had a speed reducer though as the fan is now running at 2000 RPM, making it quite a bit noisier. I suppose this is the lesser of two evils however. I may shop for a quieter fan to put in there, but I'm happy with the results.
 
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