Why clean your pc? (or “What’s that burning smell..?”)

Most of us treat computers like cars; turn it on when you want to use it, turn it off when you’re done, curse it (maybe kick it) when it doesn’t work, and think nothing of the magic happening inside. Most people also like to keep their pc tidied away under a desk (I say most – mine lives up on the desk because I like to see its shiny awesomeness, but I’m a nerd so that’s fine). Ferreting a computer away under a desk and having nothing else to do with it can have disastrous consequences; almost all mainstream domestic computers are air-cooled – they need a good supply of cool, clean air to get rid of the heat produced by the electronics inside.

Why?

Without getting too far into the tech of it all, the CPU (brain) of the computer generates a lot of heat and needs active cooling. If you were to pop open the case of your pc, you’d probably see a large heatsink and fan assembly hiding the CPU. Without the heatsink and fan to cool it, the CPU would rapidly exceed it’s maximum operating temperature and be permanently damaged. It might surprise you just how much heat they can produce – a CPU from a 3 or 4 year old pc will happily run up to around 60 degrees (C) when working hard, even with the fans on full. Brand-new pc’s run significantly cooler, but can still overheat.

The heatsink assembly works like a radiator – the thin ‘fins’ dissipate the heat from the CPU out into the air, which is then pushed away by the fan. If the fins get clogged up with dust and dirt (like the picture above) the heatsink becomes dangerously ineffective and the CPU can start to overheat. As the CPU gets hotter, several things can happen:

• nothing, until the CPU overheats and dies
• the system panics, and turns off the pc (it doesn’t care what you were in the middle of)
• the system throttles down the CPU to reduce heat (pc gets much slower at doing stuff)
• the dust/debris in the heatsink starts to burn

The first two things you’lll notice happening as they’re obvious. The third one can happen over time; the pc starts ok but gets slower and slower while you’re working on it. The fourth is rare, but terrifying; depending on the type of stuff lodged in the heatsink, it can get hot enough to start to burn. I’ve only seen it happen a couple of times in many years, but a smoking pc is not fun.

How?

Computers are very sensitive things – if you open up the case and start poking your vacuum cleaner nozzle inside, you’ll probably kill it in an interesting and hard to diagnose way. The best tool for safe cleaning is a can of compressed air. Giving the pc a good clean will involve opening up the case and getting inside it – if your pc is under warranty, or you’re not comfortable doing this yourself, get a professional involved.

Step 1 – having a good look – get down on the floor with your pc (say hi), and look for dust around the case. Most pc cases have vents on the front and sides – have a look at how dusty the vents are – if there’s plenty of dust in them, then there’ll be plenty of dust inside too.

Step 2 – start blowing – get your compressed air and start to blast away at the vents and round the back where all the connectors / ports are. This will likely blow more dust inside the pc, so don’t do this unless you’re aiming to clean inside too.

Step 3 – get inside – disconnect all the peripherals from the pc (mouse / keyboard / speakers etc). If you’re not comfortable with reconnecting them all, get some help or carefully record what goes where before disconnecting. KEEP THE POWER CORD IN (or reconnect it once you’ve got the pc somewhere easy to clean it – this is important as it allows the pc to remain earthed and helps to protect it from static electricity. Obviously, the pc should be off while being cleaned. Unscrew the side panel to get access to the internal components (this is normally the left-hand side panel as you’re looking at the front of the pc).

Step 4 – more blowing – you should now be able to see the inside of the pc, all the fans and heatsinks, and the incredible amount of dust that gets inside a pc. Start methodically cleaning the fans and heatsinks. Make sure you don’t touch the electronic components with your hands, clothes, hair, or the nozzle from the air can. The best way to clean the CPU heatsink is to steady the fan with a finger, and blast the air through the fan into the heatsink – you should be rewarded with a shower of dust and debris (which will probably head straight for your face). Work your way methodically around the system, cleaning the fans and exposed components; then blast out the loose dust in the case.

Step 5 – area cleaning – close up the pc case and move it out the way. Clean the area you’ve just covered in dust, then clean the area that the pc normally lives in. Thoroughly. There’s no point cleaning out the pc then letting it suck a ton of dust straight back in again.

Step 6 – reconnect – put your pc back, and reconnect all the peripherals. Start it up and enjoy your clean and happy computer.

Laptops / iMacs

If you have a laptop or modern iMac, your regular maintenance is a lot simpler. Turn it off, and blast compressed air into the cooling vents and pretty much any hole you can find.

How often?

Ideally, every couple of months. It really depends on how dusty it is where your pc lives. The best indicator is the amount of dust stuck in the front vents – if they’re looking clogged it’s time to have a clean.

Just to reiterate, if you’re not comfortable with any stage of the clean, don’t do it. There are plenty of independent pc support shops that will have a fixed price ‘spring clean’ service, possibly offered while you wait.

Craig

Craig graduated (some time ago) with a degree in Engineering Geology & Geotechnics and joined WDL in 2009, initially as a web developer. Over time he became responsible for our technical support, servers, internal systems and all those spare cables that you find hanging around offices. Recently, he has taken on extra duties and is now also Head of Fish.

More Posts - Meet the rest of the team