Dell Optiplex 780 system fan keeps running on high

[itbedguy]

I installed Ubuntu server 16.04.3 on an old Dell Optiplex from 2011 with an Intel Core 2 Duo E7500 @2.93Ghz, 2 cores. I’m using it as a Plex server. Plex runs pretty well considering how dated this machine is. The only issue is that the system fans run high speed all the time, regardless if the CPU is being taxed or not. I suspect it is some sort of ACPI compatibility issue. I’m somewhat a newbie when it comes to Linux. Are there any Dell specific drivers I could try to fix the problem? Any help is greatly appreciated.

[DuckHook]

Welcome to the forums, itbedguy.

The combination of lm-sensors and fancontrol may work for you:

sudo apt update && sudo apt install lm-sensors fancontrol

Instructions on setting up/using lm-sensors: https://help.ubuntu.com/community/SensorInstallHowto
Instructions for setting up fancontrol are further down the same page: https://help.ubuntu.com/community/Se..._sensor_values

Note that fancontrol may not work on your machine, and lm-sensors is not always easy to set up. If you are lucky, your exact MOBO and chipset will be recognized with proper values already populated. Sometimes, you need to create a config file for your mobo/CPU/GPU/chipets. In the worst case, your MOBO is not recognized. But—such caveats aside—once set up properly, it is pretty much boot and forget.

[gordintoronto]

Any chance the CPU heat sink is clogged up, or the fan has stopped working? I just went through this with my desktop.

[QIII]

If you don't have any monitoring set up, reboot and immediately enter your BIOS setup to see if there is a temp indicator. Let us know what you find.

[itbedguy]

Thanks everyone for the information. Turns out upon closer examination that a bad noisy fan in the power supply is the culprit. My apologies for not noticing that before, but, at least I learned a few things in the process.

[sccman]

No problem

I'm not sure if you're doing it but just a friendly safety warning: DO NOT OPEN THE POWER SUPPLY UNDER ANY CIRCUMSTANCES. They have electricity that runs through them even after you unplug it from the wall and computer. Touching the wrong wire can actually kill you from the electricity. We'd rather you be alive than dead.

[DuckHook]

…a bad noisy fan in the power supply is the culprit…

…DO NOT OPEN THE POWER SUPPLY UNDER ANY CIRCUMSTANCES. They have electricity that runs through them even after you unplug it from the wall and computer. Touching the wrong wire can actually kill you from the electricity. We'd rather you be alive than dead.

↑+1

A new PSU is a cheap fix. You might even be able to salvage an old PSU from some computer shop for next to nothing.

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Good Luck and Happy Ubuntuing!