Archived from groups: alt.comp.periphs.mainboard.asus (
More info?)
In article <3c741277.0404190246.172d3583@posting.google.com>,
scfisher_list@ntlworld.com (Steve Fisher) wrote:
> nospam@needed.com (Paul) wrote in message
news:<nospam-1804041539020001@192.168.1.177>...
> > In article <Hhugc.456$Gq3.370@newsfe1-win>, "Stephen Fisher"
> > <scfisher_listIGNORETHIS@NOSPAMntlworld.com> wrote:
> >
> > > First PC build is now working, no problems with insallation of mother
> > > board/processor/memory/sata hard drive/graphics card or installation of XP
> > > apart from.....
> > >
> > > The case i have has some audio connectors on the front (line
> > > in/microphone).
> > >
> > > From the inside of the case there are two sets of four wires which need
> > > connecting to the motherboard.
> > >
> > > One bunch is labelled
> > >
> > > GND (1)
> > > MIC IN (2)
> > > L In (3)
> > > L Out (4)
> > >
> > > Other bunch is labelled
> > >
> > > GND (5)
> > > MIC IN (6)
> > > R Out (7)
> > > R In (8)
> > >
> > > What i would like some to tell me is how these connect into Front Panel
> > > Audio Connector on motherboard (A7N8X-E)
> > >
> > > The options are
> > >
> > > MIC2 AGND
> > > MICPWR +5V
> > > Line Out_R BLINE_OUT_R
> > > NOT USED
> > > Line Out_L BLINE_OUT_L
> > >
> > >
> > > I've labelled the wires from case (1) to (8) it would be nice if someone
> > > could put the releavnat no next to the appropriate option on motherboard
> > > connector/
> > >
> > > Regards
> > >
> > >
> > > Stephen Fisher
> >
> > MIC_IN * MIC2 x x AGND ---- GND
> > MIC_IN * MICPWR x x +5VA
> > R_In <--- Line Out_R x x BLINE_OUT_R <--- R_Out
> > NC x
> > L_In <--- Line Out_L x x BLINE_OUT_L <--- L_Out
> >
> > The wires labelled MIC_IN will be going to Tip and Ring.
> > What you will have to decide, is which is which. Look
> > at this web page, and the section entitled "Connecting the
> > circuit to soundcard". It has a figure of a 1/8" stereo
> > plug, showing the Tip goes to MIC2 and Ring goes to
> > MICPWR or bias. You are going to have to figure out which
> > Mic_In signal is Tip and which is Ring. (The bottom contact,
> > called Sleeve, will be one of the GND signals.)
> >
> >
http://www.epanorama.net/circuits/dynamic_to_electretinput.html
> >
> > / \
> > MIC2 ------| |
> > \ /
> > +===+
> > MICPWR -----| | 3.5mm plug
> > |===| to soundcard
> > | |
> > GND -------| |
> > | |
> > +=======+
> > | |
> >
> > For the two grounds, the normal convention is, one goes
> > with the Mic circuit and the other one goes with the
> > stereo output. If you have an ohmmeter, you could test
> > the two GND signals and see if they are joined at the
> > computer case end. If they read zero ohms, then you'll
> > only need to connect one of the GND signals, leaving the
> > other one disconnected (make sure it doesn't make contact
> > with the wrong thing inside the case).
> >
> > If they are independent of one another, then you will need
> > to find another header pin on the motherboard which is a
> > GND. For example, the "Aux" audio header, has two GND pins
> > in the center of the 1x4 header. You could use one of those
> > GND pins for the second case wire. Since the pin is short,
> > this might not work too well - the reason I suggest this one,
> > is the GND signal in this case is next to the audio chip,
> > and so might be considered a "quiet" ground, whereas picking
> > a GND off a USB header, there could be digital noise on
> > that ground. Try different GND pins for the GND wire if
> > you are having problems with noise.
> >
> > HTH,
> > Paul
>
> Paul,
>
> Am i correct in my understanding that i need to do the following:
>
> 1) Check if 2 GNDs are connected and if thety are connect one to
> motherboard and make sure other is safe.
> If grounds are not connected find another GND and use that.
I was suggesting that if you use a multimeter and test for
continuity between the two GND signals, and they are shorted
together on the case, then only one of the wires would need
to be connected (i.e. the case manufacturer in that instance
has redundant GND connections). The benefit of only connecting
the one ground, is the FP_AUDIO header supplies all your needs.
If there is an open circuit between the two GND pins, or you
do not own a multimeter/ohmmeter etc, you will need to connect
the two GND pins. One GND can go to the FP_AUDIO, and you'll have
to examine the pinout diagrams for the other headers on the
motherboard, as for example, the USB headers have GND on them
and could be used for that purpose.
>
> 2) Connect the 2 MIC_IN pins. Can i just try them one way check front
> microphone and front headphone inputs and if that doesn't work try
> the second way. Can the board be damaged by getting the
>
> MIC In to MIC PWR
> MIC IN to MIC2
>
> muddled up?
That sound like an excellent plan. If you have an electret (amplified
microphone), in many cases is won't matter which combo you wire up.
A passive microphone (dynamic microphone - device looks like a
small speaker, being used as a mic) will give a more definitive
test, as one wiring combo will be dead, and the other will work.
With the electret for your test, the mic boost check box in the
mixer won't be needed, but the passive would need +20dB of boost
to be heard.
Another way to test, is with a stereo signal source that has a
balance control. Something with a line_out jack for example.
On a line_out, the Tip of the jack is the Left channel ( and
the Ring contact is the Right channel). Adjust the balance control
so that only the Left signal is driven.
Now, connect one of the Mic_In wires to the MIC2 pin on the
FP_AUDIO. Then, plug in the stereo source signal which only
has a Left signal driving out. You should hear that signal
if the Mic_In wire that goes to Tip is being used. You can
then leave that wire on the MIC2 pin, as the other pin will
be the Ring contact, and it goes to MICPWR. Try the other
wire as a candidate for the MIC2 pin, until you find a wire
that delivers the Left signal successfully to the mic input.
I think this test is a little easier than the microphone
based testing, as with the mic, you don't know if the mic
is working before you start your test.
http://www.epanorama.net/links/pc_sound.html (ref. material)
>
> My next question is if i get the above sorted out will the rear
> connections work. when i've been searching on this subject on the
> Internet i've seen the occasional references to rear audio sound not
> working once front audio is connected up. The fact thatb i will end up
> with connections on all the pins where the jumpers were does that mean
> rear audio will continue to work.
>
Yes, the four wires R_IN, R_OUT, L_IN, L_OUT perform the
same function as the jumpers.
You have pins labelled R_IN and R_OUT, and the R_OUT signal,
for example, when connected to the FP_AUDIO header, will result
in your lime colored Line_out on the back of the computer working.
It is people who only have only a single pair of L,R wires that
cannot have audio out on the back of the computer - you have
two pair, one pair out, and the other in, so your audio will be
switched depending on whether a plug is inserted in the headset
jack on the front of the computer.
By the way, if you follow my wiring plan, and cannot get audio
from the Line_out on the back of the computer, when there is
nothing plugged into the headset jack on the front of the case,
reverse the INs and OUTs of your four wires.
Here is some ASCII_art of how the wiring works for Line_out.
This is how your computer case will work:
-------------
| |
----------| Sound |
| | Chip |
| ------| |
| | | |
| | | |
Case Front Audio | | -------------
("Interrupting" Type Jack) | |
| |
-------- 1 AGND | | Lime Lineout (Back)
| ______ 2 Line_out_R <------ |
- -| / ^ | AGND ----------+ (SLEEVE)
| | |--- 3 BLINE_OUT_R -------- | --------------------+ (RING)
| | |
| | |--- 4 BLINE_OUT_L -------- | ------------------+ (TIP)
| | v |
- -| \_____ 5 Line_out_L <----------
5="Tip", 2="Ring", 1="Sleeve" - the technical names of the three contacts on
a 1/8 inch diameter stereo plug. When headset is plugged into the
front of the case, 2--3 opens, and 4--5 opens, and there is no sound
on the back of the computer. With headset removed, the contacts close,
and there will be stereo sound on the back of the computer.
>
> Regards
>
> Steve Fisher
HTH,
Paul
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