Quiet Media PC made from Junk

Do-It-Yourself Systems
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The top was supported on all four sides, this was important as it will have to bear the weight of a heavy CRT television. I decided to paint the whole thing black as it would be more in keeping with modern AV equipment and here was my only outlay, on an aerosol can of black paint. The wood veneer was not wasted as the wood grain can still be seen, giving it a very attractive texture. The complete article is actually quite light, I could nearly put a handle on top and call it a portable.

All the components in place, ready for the top cover.

The hard drive is held vertical by a rubber strip fixed to the floor on bottom and a piece of angle screwed to both the drive and the bulkhead on top.  Last thing to be connected up were the fans. The bottle-shaped black object in the top left-hand corner of the photo above is a 12V to 7.5V 600mA adapter made to plug into a car cigarette lighter socket. This was connected to the DPDT switch, scavenged from the old stereo, to control the fan speed. I disassembled the adapter, removed the end connectors and soldered the wires to the 12V (yellow wire) and neutral line of a molex plug.  I also soldered a second live wire to the 12V pin of the molex plug. This one would bypass the adaptor and go to pin 1 of the switch. The one going through the adaptor would go to pin 3 of the switch. I would only be using one side of the switch to switch the fan voltage between 12V and 7.5V. The other side of the switch will be used to connect a bi-polar LED, as soon as I find one.

Including the stock CPU cooler and cheap noisy PSU fan, there are four fans. The CPU and one of the case fans had sensor wires. These I left intact, attached to the motherboard fan headers. I cut all the live and neutral wires from their various connectors. The neutrals I bundled together and connected to the neutral coming from the adapter. The live wires I also bundled together and connected to the central pin of the DPDT switch. Pushing the button once will establish a circuit between the central pin and pin 1, 12V. Pushing it again will break that circuit and make a circuit with pin 3, 7.5V. Later I'll try different combinations of fans, but for now I want to have the same setup as in my orignal computer case to compare the noise level.  I started up the system with 12V going to the fans and the lid off. Putting the lid on did result in a slight diminution of the sound level.  I don't think such was ever noticeable when putting the side back on a metal case. 

There are other cheap ways of doing this, using the 5V and 12V lines to get not only 5V and 12V but also 7V. Check out Cliff Anderson's Fanbus page or Silent PC Review's Get 12V, 7V or 5V for your Fans article.

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