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Installing The Power Supply And Motherboard

Best Of Tom’s Hardware: How To Build A PC
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Preparing The Case

Most cases support a range of motherboard sizes, each with a few different mounting points. These points are meant to 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 motherboard's mounting hole positions and place a standoff in each corresponding tray location. A mistake made here could potentially damage the board, but 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.

Most motherboards use a custom port arrangement and include a customized rectangular cover plate that snaps into a standardized rectangular hole on the case. Cases typically include an old-fashion standard plate that must be snapped out before inserting the new, custom replacement.

Note that the upper tabs hang down because the cover plate usually arrives 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.

Recheck standoff positions before inserting the motherboard at a slight port-first angle, aligning ports with cover plate holes while guiding the motherboard until it rests flat against the standoffs. Grounding tabs on the port covers will typically push the motherboard out of position by approximately half the hole's width, 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 easiest to install prior to motherboard installation. It's typically held in place with four coarsely-threaded screws.

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