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Step 11: Install Motherboard And Power Supply

How To Build A PC: From Component Selection To Installation
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Most enclosures support a range of motherboard sizes, each with a few different mounting points. These points connect a layer of the motherboard called the ground plane to the case's mounting tray, reducing signal crosstalk due to radio frequency interference (RFI). Thus, the mounting points are usually grounded.

Misaligned mounting points could contact a hot trace on the motherboard's back side, so case manufacturers usually make them removable via metal spacers called standoffs. It's important to observe the exact location of each mounting hole in the motherboard before placing a standoff in the corresponding tray location. A mistake made here could potentially damage the board, though the most likely result of an improperly-placed standoff is a system that simply refuses to power on. Arrows in the photo below illustrate the matching mounting points where standoffs were placed.

The ATX form factors specifies the size and location of a rectangular plate, called an I/O shield, which fills the gaps around the ports and connectors on the back of the motherboard. That is to say, an I/O shield fits a customized port selection to a standardized hole in the chassis. Cases often include an old-fashioned standard plate that must be snapped out before inserting the new, custom replacement.

Note that the upper tabs of this I/O shield hang down because it arrived in a semi-flattened state. These need to be bent approximately ninety-degrees from the surface to prevent them from blocking nearby ports during motherboard installation. The left tab in the photo below has been bent to the proper orientation. Many of today’s most popular boards instead use foil-faced foam to contact the ports.

Recheck standoff positions before inserting the motherboard at a slight angle, aligning ports with cover plate holes while guiding the board until it rests flat against the standoffs. Grounding tabs or foil-faced foam on the I/O shield will typically push the motherboard out of position, but the board should be easy to push into place. Align one hole perfectly with the standoff and affix a screw, then push the board into alignment for a second hole before tightening the second screw. The first two screws should prevent the board from twisting out of position while installing the remaining screws.

The power supply is usually secured with four coarsely-threaded screws, though it’s not always mounted to the back of the case. Some enclosures relocate the power supply and use an extension cable to place power on the back. Variations in design may demand that the power supply is installed before the motherboard, as specified in the case’s manual or installation guide.

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  • 0 Hide
    IRONBATMAN , 23 June 2014 10:50
    I usually recommend Newegg's Tutorial to my friends. It's easier to watch than to read :p 
  • 2 Hide
    cats_Paw , 23 June 2014 13:37
    Step One: ask yourself what you want the PC to do, to have a general idea what kind of power and money you will be spending on it. Starting with a case is like buying clothes to a party before you know what kind of party it will be.

    In fact, the tower is sort of the last thing I think about, since it has to fitt the criteria of all the other components. (size of GPU, size of CPU cooler, size of PSU, Air or water cooled, Amount of fans/airflow, extras like cathodes or not, etc).

    Usually for home use I start from the CPU, for gaming I start from the GPU.

    Finally, insead of giving us certain models to look at, it is far better to give us a place where we can check a large amount of models and decide for ourselves (assuming there is no incentive to show us those models, it would be not only better, but easier).
  • 0 Hide
    mi1ez , 24 June 2014 22:49
    Why the hell is a tech website still offering up dimensions in inches?!