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What causes a computer power supply to fail?

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Joined Dec 19, 2009
Apart from dust and fan's Electrolytic capacitors are also to blame Normally you can see this if you remove the power supply , Open the power supply up , and with a quick visual inspection , you will notice the Capacitors swollen and about to burst

Cause "Working voltages too low manufacturers don't overate them slightly" Very tight build , Placed to close to components such as heat sinks and Load resistors where the heat giving off by these devices cause the normal operating temperature of the reservoir capacitors to be exceeded and consequently fail

Replacing these with high quality high temperature capacitors is an answer

You will never ever get manufacturers to do this unfortunately

The price you pay for mass production and cheap manufacture

Responsible for a number of MUP.SYS failures on boot up "Common cause of this problem power supply " Ripple and no smoothing / regulation of supplies due to Caps


Joined Jul 26, 2010
I hate to say it, but half the power supplies out there rarely last for more than a year or two before they start developing one kind of problem or another. I've torn a few failed ones apart and it's pretty obvious that in most they use the cheapest caps they can find, I only found one that actually just had a cold solder connection.

Another thing they do is to highly overrate these things. Sometimes a 450W supply may add up to that but most of the power is to the 3.3V & 5V rails with very little going to the 12V rail(s) which have become the most important part of a supply now. Not only have graphics chips greatly increased their consumption of 12V but most all motherboards nowadays switch the 12V rail down to get the core voltage for the CPU, many of which draw a large amount of wattage too.

On the plus side modern hard drive consumption has actually decreased, my 1 TB drives idle at 4w and my 2 TB drives only need 6W when they're just sitting there spinning.
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Joined Mar 24, 2008
I think I mentioned this before, but I buy the cheapest I can get, and their average lifespan is around 4 years. You may want to look at the dust buildups if you're getting less life, air flow and temperature is critical for the lifespan. I also run my house on the cold side.
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