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I have a Compaq Presario R4000 running Ubuntu Linux 9.10 karmic. The system runs very hot and one of the fans is wither never running or always running at the slowest speed. For a while I thought the fan was dead but I just updated the BIOS (Phoenix BIOS) and during the update, that fan suddenly kicked in at full speed!

How can I get that fan to spin up during normal usage? I have tried sensors-detect but all it found was k8temp, no fans...

(SpeedFan under windows found no fans either)

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up vote 2 down vote accepted

It's entirely possible your laptop does not support software-based fan control. I have a Compaq Presario R3000 kicking around which does not, and, much like yours, only exposes some temperature sensors.

The fan in mine operated only as a hardware-controlled function of CPU temperature, and at a particularly lap-scorching range, too. Around 65+C it would kick up from it's lowest speed to about 60%-ish speed, and past about 70C it would hit 100%.

If sensors-detect found any sensor chips besides k8temp, however, there may still be hope: The utility you'd want to run to find controllable fans is pwmconfig. That gives you software-tunable control of fans based on sensor output, much like SpeedFan's automatic fan control mode.

Edit: Additionally, you might want to see if that second fan spins up under a particularly heavy CPU load. The linux version of Prime95 ought to be more than sufficient to generate enough heat to see if that's the case. Watch your temperatures, of course!

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Well when running BOINC, the temperature rose to 144°C with no fan activity. So if it's controlled by hardware then the hardware isn't working. If doing a BIOS update made the fan run at full speed shouldn't there be some other software based way of getting the same effect? – Josh Apr 26 '10 at 13:59
CELSIUS? 144C is alarmingly close to the melting point of solder. If you're absolutely sure it was C and not F, your laptop is in serious need of repair -- something is very, very wrong. Your CPU should have shut down well before it hit 100C. The BIOS updater probably poked some very low-level thing to get the fans spinning, as it was already in a position to do so. This was likely a significantly lower-level operation than can be easily exposed in modern operating systems, so for all intents and purposes, it's not software controllable. – Dylan B. Apr 27 '10 at 8:27
Well I have the temperature monitors in Fahrenheit, and two of them were reading 288°F I believe. The third one was far lower, but I forgot now what exactly it was. 110°F maybe? Something is clearly wrong and I suspect I need to be looking for a new machine. – Josh Apr 27 '10 at 17:57

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