installing motherboard into the cabinet

Installing the Motherboard
The next steps to test fit the motherboard in the case. Use two hands to hold the motherboard over any existing standoffs and check the fit with the I / O shield. Next, count the number of silver rimmed holes in the motherboard that line up with holes in the case (all of them should). Set the motherboard off to the side on its static bag and remove any standoffs than don't line up with the holes in your board.
Installing the Motherboard

Install standoffs in the case holes that match your motherboard. Do not use standoffs that ship with the motherboard unless you remove all the standoffs that are installed in the case. Slight differences in standoff height can put unacceptable stress on the motherboard. The standoffs that shipped with this case are the standard brass type, which can be tightened with a nut driver or pliers, but don’t' over tighten or they may break.

Count the number of standoffs installed and set aside that number of screws. Reinstall the motherboard in the case, securing the corners first. It's usually best to start with the corner by the memory sockets, across from the I / O core. The little tabs on the I / O shield can apply enough spring force that you need to really keep the motherboard pushed into the shield as you install the screw. Secure the other corners, and then fill in the other screws. If you finish with one of you set-aside screws left over, remove the motherboard and takeout the standoff that didn't line up with a hole.

Here you can see I / O core of the installed motherboard properly aligned with the I / O shield. Above the I / O core are the two exhaust fans. The airflow direction can be confirmed by noting that the labels on the fan motors are visible through the grate.

The next step is to attach main ATX power connector to the motherboard. The 20-wire connector is keyed so that is can only be installed one way, and it automatically secured by the plastic spring latch. The power supply should not be plugged in or switched on until build is complete.

With the introduction of the Pentium 4, Intel required an additional 12 V lead from the power supply to the motherboard. Some P4 motherboard use an old-fashioned AT power connector to supply additional power for the CPU or AGP Pro slot, but none of our builds use one of these. We attach the 4-wire 12 V power connector next to the I / O core.

The muffin fan that we previously installed in the front of the case needs a power connection, and one is conveniently located nearby on the corner of the motherboard. Using the motherboard connection means the computer can monitor the fan status. The muffin fan in our Athlon / P4 build is powered directly from a power supply lead.

The most important of the front panel leads to the motherboard is the power switch. This two-wire connector can go on the proper two posts either way, unlike LEDs, which will only work with the correct polarity. The circular unit below and slightly to the left of the connection block is an onboard piezoelectric speaker, eliminating the need fro a case speaker connection.