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DIY Variable speed 80mm Fan Guide

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The first thing needed to make a variable speed fan is a fan fitted with a thermal sensor , there have been a few of these made through out the years . The fan Im using is one from a power supply, out of a 486 computer ( this should give you some idea of how old this idea is ) . The thermal sensor is woe full to say the least , with the fan idling at low rpm , and possibly coming on at around 100deg ? , not the best temp to turn on the rpm I can assure you . So what to do with these fans ? 

Remove the thermal sensor , and replace it with a 10k pot .

The first picture is of our 10k pot , got mine from Dick Smith , for the sum of $1.90 . Using a multimeter , just make sure you have the right two connections to solder to . The second picture , is of the fan after the sensor was removed , sorry about that , should have gotten a pic with the sensor in place .

To remove the thermal sensor , just use the soldering iron to heat up the solder joints and pull the sensor out with a pair of needle nose pliers . You can see that Ive melted a bit of the plastic with the soldering iron , this is ok .

 What we do now is solder in two leads , which will then be soldered to the pot .

Here are two pictures showing you how simple it is , you only need basic soldering skills to do this . Just make sure the ends of the wire have been tined ( soldered ) put the wire in place and placing the soldering iron in from the hole the lead is soldered in place . Dont use to much solder , you dont need it , and you dont want to short the joint , as that would make the pot next to useless . ( constant full speed ) 

Drilling an appropriate sized hole for the pot in the side cover , I now have a variable speed fan in my side cover . So with a little planning there is no reason why every 80mm fan in your case could not be of the variable speed kind . Full power on those warm days and backed of for those Brrrrr winter days , when the slightest breeze sends a cold shiver down your spine . Peter at NucleusComputer has a few of these fans left  , check out there web site here .

And there is no reason what so ever that you could not do the same thing with the Thermaltake Smart case fan , it pumps out about double the AMPs , but I think that the 10k pot should still be OK ? at $1.90 its not going to break the bank . Just remove the thermal sensor , solder on new leads , and connect to the pot , and you have the speed you want at your finger tips .

Matt Korhonen