How to Replace a CPU Fan

On a heavily used computer, the fact that there are mechanical parts involved will eventually become apparent — by their failure. A hard-core gamer or someone involved in a computer related home business will eventually start to hear strange sounds coming from their computer’s tower.

One of these sounds could be described as a rasping or grinding noise which has a rhythm. This is a sound of a failing computer fan. Inside the case, there are several fans, but in my experience the problem fan will usually be the one which cools the CPU. At first, you may be tempted to ignore this noise, but eventually the fan will either get too slow to be effective, or it will fail outright and stop completely. It will also get louder and louder as time progresses. Since the CPU will overheat without a fan, this will usually result in the computer shutting down due to “heat fault.” If you are unlucky, the CPU may just burn up without the computer giving you a protective shutdown instead.

Because of the importance of the CPU fan, a failing one will need to be replaced, and the sooner the better. While it is possible to have the fan replaced at a computer shop, it is much smarter to just do it yourself. A computer fan is cheap — you can get them for less than $5 — and replacing one is a simple job. Here are step-by-step instructions for a common computer configuration (note that some computers have odd or proprietary setups — for those, different steps may be required.):

1. First, open your computer’s case.

2. Ground yourself to prevent static buildup. This can be done with a special antistatic device you can wear, if you want to be fancy. The free way is to ground yourself against the computer’s housing. Also, make sure to not rub up against any carpet or other static-causing items, either before you start or while you are working.

3. Find your CPU fan. It will be attached to the motherboard somehow, most likely on top of a heatsink. Usually the heatsink is a boxy thing, but sometimes it will be fancier and have a different shape. The heatsink itself has fins, but these will be likely hidden from view by the CPU fan on top of them.

4. Once you locate the fan, the next step is fairly obvious. You need to remove it. Even though fans and heat sinks are often sold as a unit, you do not need to take the heatsink off. You can usually simply unscrew the fan from the heatsink. This saves you from having to reinstall a heatsink, and also makes it so you will not have to reapply thermal paste to the CPU.

5. Measure the fan. Measure straight across, rather than on the diagonal. This measurement needs to include the fan’s housing. You will need to measure in millimeters, since computer fans use the metric system.

6. Buy another fan. The best places to buy fans and other computer components are online. Newegg and TigerDirect have great deals on all of these types of things. But you may not want to wait for delivery, since this is a critical computer part and you’ll need it to be able to use your computer again. In that case, take your measurement to your local computer store and buy one there. Buying one locally, however, may mean you have to settle for buying the entire fan-heatsink unit, or getting a brand or type you may not prefer. Therefore, it is best to buy a computer fan as soon as you hear the telltale noise which warns of impending fan doom.

7. Once you have your fan, ground yourself, and then screw it onto the old heatsink. If the replacement fan comes with a new heatsink, just detach that one and put the fan onto the one that’s already on the motherboard. Plug in all the connections. There should be at least one connection, through which it will get its power. There may also be a connection which leads to some type of speed controller. If you bought a fancy fan which lights up or has other types of power consuming bells and whistles, it may need to be attached to the power supply (regular fans often only attach to a socket on the motherboard).

That is all it takes to replace the CPU fan in a machine with a typical configuration. It is a simple 5 to 10 minute job. The part which takes the longest isn’t the actual installation; it’s getting the new fan. Whether you have to go to a store near you, or buy one online, it’s a part most people don’t have on hand. If you want to avoid this delay, simply measure your current fan, and buy a spare while it is still working. That way, you not only will not have much downtime if your fan fails, but you can get the perfect one online for the cheap price without having to buy any unnecessary components like new heatsinks.

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February 13, 2012
Posted in DIY — Knowledge Buff @ 5:08 PM

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