# Computer fan wont stop running



## del schisler (Aug 22, 2010)

minellm1 said:


> Hello,
> 
> I recently changed the CMOS battery and now my fan won't stop running! I've removed the heat sink, cleaned it up, it it back in and the fan is always going. Even from a cold boot up the fan goes at full and in the bios, it shows a 68c temperature. There is no way it could be that hot! Any ideas as to why this is happening?
> 
> Thanks, Mike.


did you put heat sink grease back on the top of the cpu , if not do that the heat is not transfering to the heat sink, my guess , go to a comp. store and they should give you some, it should be white grease put a lot on it will squeez out which will be ok it doesn't melt. good luck, now watch that the cpu doesn't come out of the socket.


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## RWolff (Jan 27, 2013)

minellm1 said:


> Hello,
> 
> I recently changed the CMOS battery and now my fan won't stop running! I've removed the heat sink, cleaned it up, it it back in and the fan is always going. Even from a cold boot up the fan goes at full and in the bios, it shows a 68c temperature. There is no way it could be that hot! Any ideas as to why this is happening?
> 
> Thanks, Mike.


I've not seen this issue, but if the fan is running all the time and the temperature shows 154 degrees F (69 C) then something *is* getting hot enough to turn the fan on even if you don't think it is.
Just because you turn the computer off doesn't mean it goes to dead cold, it's still plugged in and putting power into the power supply.
I know on my machines even when they are off I can still see a red led lit up inside the case thru the fan grill.
154 degrees F is not super hot but it's not good for the electronics and they won't last as long. You'd usually see this kind of temperature in a computer doing a lot of work.

I vote up for the heat sink grease from the previous reply, but it may be more than that, opening the case up you might have dislodged a conenctor or something, or some component decided to throw in the towel by coincidence.
If the grease doesn't cure it then I would not continue running it in this state of condition without having it checked out.

There is a fan controll software for mac, I assume for pc as well, I normally never shut my machines off they run 24/7, and I have the software that allows control of the fan speeds and have one adjusted to run faster so the
temperatures are never more than 100-110 F (37-43 C)
Right now my main machine is 106 degrees F.

I wouldn't recommend this software to slow down/shut off your fan, assume that temperature is RIGHT and act acordingly otherwise your machine could have a problem enough it fries something.


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## bbo (Feb 28, 2010)

also note you should not use "a lot" of grease (thermal compound) between the heat sink and the processor. the grease is just there to help make contact. The more you put in there, the more the heat has to travel through to the heat sink. The standard is to use some no larger than a grain of rice.

I would check all connections for loose or damaged wires. my guess is you didn't plug something back in or flipped a dip switch somewhere or have a damaged wire.


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## TheBobmanNH (Oct 23, 2012)

I would back up a bit here. All you did was pop out the CMOS battery and put in a new one, and then your CPU started reporting it was overheating(ish)? And your first thought was to take off hte heat sink?

Seems more likely resetting your CMOS caused the controller to mis-read something. There's probably a CMOS setting about which processor you have, and it's mis-set, or one of a dozen other possibilities. Go carefully through every CMOS setting and make sure you understand what it means and why it is set like it is.


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## minellm1 (Apr 15, 2011)

No my first thought was that the something changed in the bios. So I checked the settings, reloaded to default, made sure the smart fan was enabled and then rebooted. I later tried cleaning the heat sink... 
I have no idea why but I reset the bios again
And now it seems to work like normal? Not sure how the temperature reads completely different after the I restore the defaults, but it's working fine now!! Strange. 
Thanks for the suggestions.


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## user1007 (Sep 23, 2009)

Is this a laptop by chance?

The overheating may be your battery acting up. One of similar ilk grounded an entire breed of passenger aircraft.


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## rossfingal (Mar 20, 2011)

If you remove the CMOS bat. -
the settings for the BIOS are erased.
The BIOS doesn't know what settings to use -
"Default" usually is a good place to start.

Depending on the BIOS -
sometimes you have to go in and set them yourself.

Never heard of using "heat-sink" paste on a CMOS bat. -
CPU - yes.


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