Computer Assembly - How To Assemble A PC
Connect The PN1 And PN2 Indicators
The computer case provides PN1 and PN2 connectors that need to be connected to the PN1 and PN2 headers on the motherboard. These connectors make a connection between the computer case and the computer (via the motherboard). It is these connectors that allow the power and reset buttons on the front of the case to work, the LEDs (one indicating the computer has power, the other indicating the hard drive is being accessed) on the front of the case to work, and the built-in speaker to work. The PN1 and PN2 headers are located on the MSI K8N Neo Platinum motherboard as shown circled in blue.
As can be seen in the picture below, there are five cables that need to be connected into specific positions of the PN1 and PN2 headers. The motherboard manual should be consulted for detailed information regarding the PN1 and PN2 headers. The nasty thing about these cables is that they are not keyed, so they can be plugged in the wrong way around or on the wrong set of pins. The cables are POWER SW (for the power button on the front of the computer case), SPEAKER (for the internal speaker - the one that just goes "beep"), POWER LED (for the LED on the front of the computer case), RESET SW (for the reset button on the front of the computer case), and HDD LED (for the LED on the front of computer case that lights whenever the hard drive is accessed).
Here are the same five cables flipped over. Notice that each one has a little triangle which identifies one particular pin. These little triangles can be very difficult to see, even with the naked eye. In the photograph below, I have one triangle on one cable circled in yellow. If you click on the picture to enlarge it, you can easily see all five triangles, one on each cable. And notice that each triangle is pointing out the black wire. The documentation that comes with the Antec manual states for these cables that the black wire should be connected to ground, so one might guess that the triangle identifies the ground wire. I wanted to be sure about this since it might be helpful in connecting the cables to the motherboard correctly, so I spoke with Antec Technical Support about it. I was told that the triangle is really not important, but the important thing is that the black (or white) wire is ground and the colored wire is power. And, in fact, I have seen on other Antec cases that the arrow does sometimes point to the colored wire.
Ok, that's all good. All the cables have one black wire and one colored wire - except for the RESET SW cable on the far right. It also has two wires, one black and one white, but no colored wire. Well, more about that in a moment.
The motherboard manual will indicate which PN1 and PN2 header pins are for each cable connector, and will also indicate which header pin is the header pin for ground and power. The motherboard manual may describe the pin with ground as the "pull down", such as "Hard Disk LED pull-down" in the MSI K8N Neo Platinum motherboard manual for the motherboard header HDD LED pins. Similarly, it describes the pin with power as the "pull-up", namely the "Hard Disk LED pull-up".
As it turns out, only the LED's are a problem if their cables are connected the wrong way around. The LED's are diodes, so they have polarity. If you have an LED cable on the right pins, but the wrong way around, then the LED won't light up. It won't hurt anything, either. For the LED to work, line up the black wire on the cable connector with the motherboard header pin identified as ground (GND, or pull-down). Two of the cables are for LED's, the POWER LED cable and the HDD LED cable.
The other three cables, POWER SW, SPEAKER and RESET SW, can be connected either way. The motherboard manual may still identify one of the motherboard header pins for the connector as ground, but it will still work whether or not it is the black, ground wire that is connected to it. I verified this myself for all three of these cables by trying them both ways. The power switch, reset switch, and speaker all worked with their corresponding cables connected either way. And I also verified that the LEDs do not work when their cables are connected the wrong way around. So for the RESET SW cable in particular, which has one black wire and one white wire, it doesn't really matter which one is ground. It has no polarity so it doesn't matter which way it is connected.
Knowing all this is quite a bit helpful. It means that if you at least get the cables on the right pins then that will be sufficient. Only the two cables for the LEDs could be the wrong way around, and that won't hurt anything. It just means the LED's won't work until the cable is turned around.
On the MSI K8N Neo Platinum motherboard, the group of pins which comprise the PN1 and PN2 headers are in two halves which the motherboard labels "JFP1" and "JFP2". So you'll know where to find them, I've pointed out the "JFP1" and "JFP2" labels with yellow. These labels are also referenced in the MSI K8N Neo Platinum motherboard and they can help identify how to make the connections.
Here are the five cables connected into the PN1 and PN2 headers.
Here are the three cables
in the back in their position.
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And here are the two cables
in the front in their position.
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And here's how the computer looks assembled thus far. Everything we want installed inside of the computer for the first boot is in place.
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© 2001-2008, Rob Williams, all rights reserved.
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