(e-mail address removed) (Paul) wrote in message
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.
HTH,
Paul
