Together with your motherboard came some I/O brackets, such as more USB ports, Firewire ports and audio jacks (see Figure 18). It is time to connect them to the motherboard, but leaving them uninstalled from the case for now. Of course you can install them later to the motherboard, but once again it is easier to install them while the motherboard isn't inside the case yet.
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Figure 18: I/O brackets from the motherboard.
You should install them following the directions presented on the motherboard manual. We cannot publish were exactly they should be installed since it varies depending on the motherboard model.
Next, install the flat cables coming from the hard disk drive, optical units and floppy disk drive. If you didn't install these devices to the case yet now it is a good time to do so.
The cable from the hard disk drive must be installed on the IDE1 (primary) port and the cable from the optical unit must be installed on the IDE2 (secondary) port. The floppy cable should be installed on the floppy port. To install the cable, just pay attention on the red wire, it should be installed facing the "pin 1" marking on the motherboard. This marking is usually a number "1" or "2" painted on one of the sides of the connector (the opposite side should be marked "40" or "39", or "33" or "34" in the case of the floppy port).
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Figure 19: Cables from the hard disk drive, optical unit and floppy disk drive correctly installed.
The next step is connecting the power supply. The power supply has one 20-pin connector and your motherboard can have an extra 4-pin connector called ATX12V, which should also be installed (not all motherboards have this extra connector). You may need to lift the motherboard in a 45º angle with the table you are using to assemble your PC, since usually the wires from the power supply aren't long enough to reach the motherboard while it is on the table outside the case.
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Figure 20: Installing the power supply connector.
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Figure 21: Installing the ATX12V connector (only if your motherboard has it).
