Cooling a notebook computer on a deadline

Thursday 10pm knew this notebook computer fan is dying, way noisy. By 11pm knew a warranty replacement would be here Monday at best [got here Wednesday]. Working on a different computer would have been daunting. How to keep this one working?

Tried to install software to control fan speed, maybe avoid resonance frequencies. No luck despite several related utilities such as GNOME Sensors Applet, fancontrol, and dellfand (found via I8kfanGUI). Reading the fan speed was possible, controlling it wasn’t. Went to sleep.

Friday morning decided to blow air through the computer with a fan we had made for breathing clean air when soldering: An old computer fan on a cell phone charger. Apparently a blade had broken, so it was rattling too much. Time to make another one like it.

Found fan on motherboard on kid’s bookshelf. Ran it from adjustable power supply to find right voltage for reasonable fan speed. For a 12V DC labeled fan that was about 7V. Found a leftover power supply 6V DC. Verified with multimeter it did output a voltage matching its label, verified with adjustable power supply 6V would spin fast enough. Cut wires, soldered wires, hot glued and electrical taped it up. Grabbed leftover lumber and kids’ building blocks and stuck it under the notebook, aligned to blow where the built-in fan should blow.

notebook external fan

Making a Notebook External Fan

All is good now. Watching temperature in the top GNOME Panel with Hardware Sensors Monitor. Got it from RPMForge with

yum install gnome-applet-sensors

Added it with right-clicking in top edge panel, Add to Panel… Showed more sensors after running

sensors-detect

which may only have been possible after

yum install lm_sensors

The external fan is blowing enough air for the processor heatsink to stay cool enough, between 42°C and 50-something °C. Barely any internal fan noise – the defective internal fan now doesn’t come on much, and if so it sounds as if it has an easier time – less effort courtesy of the external fan.

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