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View Full Version : My first build, question about connecting case's front panel USB and audio



sournotessx
01-26-2012, 07:45 PM
So last night I built my first computer. I ran into a problem with the optical drive, so I haven't loaded and OS, but it boots into BIOS and everything.

So I am trying to connect my front panel USB and audio/microphone cables. (This is my case http://www.newegg.com/Product/Product.aspx?Item=N82E16811119227). However, when I looked at the manual for my motherboard (http://www.newegg.com/Product/Product.aspx?Item=N82E16813130569), the pins to connect the two don't match. They match physically, but the pin layout in the manuals are different. Here are pictures from my manual. The 2 chords I want to connect are USB, and AC'97 or HD AUDIO (I'm not sure which I want, honestly).

This is the picture from my case's manual. I did not include the pin layout for the HD audio, please let me know if I should.
http://i32.photobucket.com/albums/d13/peglegpirate/photo1.jpg?t=1327628620

These pictures are from my MOBO manual:
http://i32.photobucket.com/albums/d13/peglegpirate/photo2.jpg
http://i32.photobucket.com/albums/d13/peglegpirate/photo3.jpg
Obviously, first one is USB.

So I haven't connected anything yet... Will this work? Will it damage my mobo? Idk what to do.

zburns
01-26-2012, 09:50 PM
sournotessx:

Your diagrams are okay. The problem is 'orientation' with respect to each other and the 'difference in the letters (words) to describe the pins in the two manuals. I have looked at both pages carefully two times.

I will give you a full and clear description of it all in the morning; and you will be able to understand it in a clear manner. Probably before 9 am EST.

zburns
01-27-2012, 09:15 AM
Good Morning:
Let's deal with the easy one first!! 'Obviously, first one is USB.' -- this is your comment at the bottom outside of the bottom picture and 'Obviously, first one is USB' refers to the 'second' picture with the male plug on the bottom and female plug housing with cable just above it. Note that on the female housing with cable coming out the back that there are no wires going into the female housing at the 'northeast corner' of the plug - at the top right. So there are 'no connections' going to pins 9 and 10 on the male plug.

Look at the male plug (mounted to the mobo) pins 1, 3, 5, & 7 on the right hand side of the plug are for the USB connection called 'zero' (screwey labeling but that is what is on the diagram). Pin 1 is the +5volt supply for USB '0'; pin 3 is the (-) minus USB signal connection, pin 5 is the (+) plus USB signal connection and pin 7 is the 'ground' (gnd) connection and this connection is 'common' to the other side of the plug but it is connected somewhere else and only at one point somewhere else to prevent the existence of a ground loop.

Pins 2, 4, 6 & 8 are for USB 1. Pin 2, the +5volt power coming in, pin 4 is USB 1 minus(-), pin 6 is USB 1 plus(+) and pin 8 is gnd.
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Comments to explain the simplicity of the circuitry. The incoming power (from the mobo) to each USB plug is (for USB 1) via pin 2 (+5v) and pin 8 (gnd). The data signals to and from the USB 1 connected device is via pins 4 (-) and pin 6 (+). The plug is wired 'symetrically' meaning the pins and circuitry on the right hand side is a mirror image of what is on the left hand side. The ground connections are 'the same electrically' but physically separated electrically except for one point back on the mobo where they join -- this type of wiring prevents what is called a 'ground loop' where 'electrical induced noise' can run around a 'circular loop' in endless fashion and 'dump induced noise' into the 'actual data' moving thru pins 4 & 6. The +5 volt voltage on pins 1 & 2, likewise originates and comes from the same point on the mobo but they are not connected at the plug for the same 'ground loop' reason or logic.

The above is the explanation for the two USB connections, USB '0' and USB '1".

zburns
01-27-2012, 11:12 AM
This post is about the mobo male connector soldered in place on the mobo. The very bottom picture above applies, but the language is in German. (irrelevant question, are you in Germany?). Going forward, I looked up the MSI manual on your mother board, there were two 'downloads' for the manual, one about 5 mbytes, the other much larger, about 12 mbs. Could not download the 12 mb version, just would not work. However, I did download the 5 mbytes manual. It looked fine. The photo you show is same as what I looked at except that my pic was in English -- picture identical to yours.

What I could not see is the cabling from the front panel. I tried Coolermaster website, and asked for a 'wiring diagram' but got nothing. I went to my ASUS motherboard manual and looked up my wiring diagram on HD vs AC'97 audio. I have a front panel cable that has two plugs attached to the end of the front panel cable where it plugs into the mobo male connector -- BUT only one of my two plugs can be used -- I had to choose between AC'97 and HD audio. (Note: this explains the difference in the pin labeling you may be seeing -- AC'97 audio much simpler wiring than HD audio).

In your manual, the index and page 2-15 refer only to HD audio, no mention is made of 'two options' for audio. So this makes it easier. According to your mobo manual, page 2-15, you can only hook up HD Audio. In the Specifications at the beginning of the manual is the following: 'Audio HD audio codec integrated by RealtekŪ ALC887, Flexible 8-channel audio with jack sensing' -- no reference to AC'97.

So coming from your front panel, you have only two maybe three possibilites. First, a single cable with two separate female plugs attached and labeled individually, HD ... on one plug and AC'97 on the other plug. Or your case is wired only for HD audio, in which case you would have only one plug -- however, your coolermaster manual that came with the case would tell you whether you have only one choice (HD audio) or two choices and two plugs (HD plug and AC'97plug) --BUT I go back to the main point, page 2-15 of the mobo manual clearly states your mobo supports only HD audio.

So it appears to me that your mobo has a male plug, circuit board mounted, with the terminals labled as you show them, and, this is the labeling for a HD Audio connection from the front panel.
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A reminder comment about your pictures. They are correct. The pics from your case inst. manual do not show the plug pinouts in 'isometric perspective' which may be confusing. The 'solid' squares on the left top USB mobo front panel connector represent the pins 'as if you are looking perpendicular to the plug as mounted on the mobo'.

The 'hollowed out' squares on the AC'97 picture are the pins for the audio male plug but the pic and description is from the case manufacturer who does not know whether your mobo supports AC'97 or HD audio. You are dealing with HD audio only, unless I have missed something -- I know this because your mobo manual refers only to HD audio in the index and on page 2-15.

I will double check this post several times and post any corrections. Any questions at all, just ask!! Good luck!!