Repair guides and support for the laptop line of Acer's Aspire series for casual home and business use.

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Why is my acer desktop case fan constantly running and at full speed?

I have an acer aspire m3802 and the case fan is running constantly on high from boot up. I have checked cpu core temperatures using Real Temp and all is normal ~35-42 C. It has had a good clean and no sign of leaking or bulging capacitors on the motherboard. I have reseated the RAM just in case this helped. Could it be a faulty fan, power supply unit or motherboard? Or any other ideas? Thanks in advance.

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it can also be due to aging thermal paste between the heatsink and processor.

before you proceed to unmount the heatsink, i would recommended you to standby a thermal paste, e.g. arctic silver is good... and a little Isopropyl alcohol (IPA) .... to clean up the dried heatsink paste in the processor.

ensure the fan fins are not blocked by dust too.

check for any possible bios updates too.

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Thanks, but it wasn't overheating - I checked that before posting. It appears to be related to the motherboard.


Mine is running all the time, too, and the computer is less than a month old. There hasn't been time to age anything!! Also, it's not hot and is sitting on a nice, flat hard surface.


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Has it always behaved like this? Or is this a new issue?

You may have to open the case to check the following:

Find the fan

Locate where the cable goes.

On older systems the fans are connected directly to the power supply with a "Molex" cable, this causes the fan to run at full power at all times.

If the fan is connected to the motherboard with a "fan header cable" then it may be fixable.

You may have to go into your BIOS settings or download a third party fan controller software.

Let me know if any of this helps.

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