In article <8h4q815sctp6v87rpqqqfnhhsjcbcllmip.DeleteThis@4ax.com>, Bill
<schifty2.DeleteThis@comcast.net> wrote:
> Hi,
>
> I'm the proud owner of a Chaintech CT-7NJL6 mb and want to buy a front
> panel with USB and audio in/out/headphones. There are a few on the
> market that I've seen, but I'm not sure if the connection on the MB
> works with it. The one I really like: SOYO BayOne Extreme 9-in-1
> USB2.0 Card Reader - Retail $22.99 Model #: BayOne Extreme
> Item #: N82E16820194502
>
> I downloaded the installation guide, and it says "The Part A connector
> of the cable # 3 follows the Intel front panel audio cable standard.
> The Part B connector is for the front panel line-in function."
>
> Part A is a cable with 5 connections and Part B is a cable with 2. I
> can see by looking at the 7NJL6 manual that there are 5 connections on
> the one side of the CN24(front panel audio connector) and on the other
> side there is room for the Part B connector, although I'm not sure
> which two I should connect it to.
>
> Anybody have any experience with this stuff?
>
> Thanks,
> Bill
Soyo Bay One product manual
<a style='text-decoration: underline;' href="http://www.soyousa.com/downloads/filedesc.php?id=2309" target="_blank">http://www.soyousa.com/downloads/filedesc.php?id=2309</a>
Motherboard manual
<a style='text-decoration: underline;' href="http://www.chaintech.com.tw/download/7xmb/7NJL6.pdf" target="_blank">http://www.chaintech.com.tw/download/7xmb/7NJL6.pdf</a>
Intel FP_AUDIO header spec page 20
<a style='text-decoration: underline;' href="http://web.archive.org/web/20040207150757/http://formfactors.org/developer/specs/fpio_design_guideline.pdf" target="_blank">http://web.archive.org/web/20040207150757/http://formfactors.org/devel...r/specs</a>
The Soyo end consists of
MIC_L GND \
MIC_R VCC |
AUD_F_R AUD_R_R +-- this part goes to the 2x5 cable.
HP_ON GND | green jack is for headphones.
AUD_F_L AUD_R_L / pink jack is for microphone (see below).
(Key) (Key)
LINE_F_R LINE_R_R \____ this part goes to the 2x2 cable
LINE_F_L LINE_R_L / (no motherboard that I know of, has a
header for Line_in. Blue jack will not
work.)
The Chaintech end is not perfectly standard:
MIC AGND
X AVDD5
Front_R R
NC
Front_L L
The Chaintech "MIC" will go to the Soyo "MIC_L". That is the Tip
contact of a 1/8" stereo jack. Since the Chaintech has "X", where
"MIC_R" would go, there is no MIC_BIAS or MIC_PWR to go to the pin.
That means, if an electret microphone is connected, it may not
receive power, and may not work. A dynamic microphone (magnet plus
wire coil) will work, with the "MIC" contact, but much gain will be
required to get that to work (even with Mic_Boost enabled, it might
not be enough gain). Now, I don't know what Chaintech's practice
might be - they could combine the Bias function with the MIC input
function, and it still might work. To summarize, if you connect a
microphone to the pink jack on your Bay One, and it doesn't work,
don't be too surprised.
In "Connecting the circuit to soundcard" here, you can see that
at a minimum, an electret microphone can work with just two
wires, and it could be that Chaintech has already connected audio
and bias together, as the MIC signal.
<a style='text-decoration: underline;' href="http://www.tkk.fi/Misc/Electronics/circuits/dynamic_to_electretinput.html" target="_blank">http://www.tkk.fi/Misc/Electronics/circuits/dynamic_to_electretinput.html</a>
I'm hoping that the Chaintech "X" notation means "No connection",
as does the more standard notation "NC", as that is used to mean
"No connection" in an electronics context.
The way the headphone signals work, is the signals on the left
column, come directly from the sound chip. The signals on the right
column, are the return signals, and those signals go to the jacks
on the back of the computer. Normally, when a motherboard comes from
the factory, there will be jumpers from "Front_R" to "R" and
"Front_L" to "L". When the Soyo 2x5 cable is connected to the
motherboard, the Bay One will bridge the signals in place of
the jumpers. The reason for this wiring, is so when you plug
headphones into the green jack on the Bay One, the Lineout on
the back of the computer will be muted. That is the way it would
normally work. Some products similar to the Bay One, cheat by
not providing the mute function, and it is kind of a 50/50 split
as to how many people like the mute function versus the non-mute
function.
In summary, just remove the jumpers from your Chaintech motherboard,
and plug in the Soyo 2x5 cable. You should get working headphones.
On the microphone, no guarantees as to whether all microphone
types are going to work. If it doesn't work, don't blame the
Bay One, cause they did the right thing on their end.
The Bay One 2x2 Line_In cable looks to be perfectly useless to me,
as I've never seen a Line_In header on a motherboard. Motherboards
can have things like Aux_In, or CD_Audio headers, but these are
1x4 headers, and the pins are a different size. I expect you'll
just have to leave the 2x2 wire dangling. The Blue jack will not
work as a result. With some creative hacking, you could connect
Aux_in to the Blue jack, but you'd need to purchase some separate
parts from an electronics store.
Now, after writing all of this, a more serious matter, is the
Bay One USB wiring is incompatible with the Chaintech CN23, CN23A,
CN23B USB headers.
Chaintech Soyo Bay One
header cable end
VCC VCC VCC VCC
D0- D1- TD- TD-
D0+ D1+ TD+ TD+
GND GND GND GND
OC2# GND <--- this needs to be modified
The Soyo Bay One has a perfectly reasonable design. The
VCC, TD-, TD+, GND are the set of four pins that correspond
to the four contacts inside a standard USB connector. Notice
there are two groups of them, suitable for two USB connectors.
The bottom GND connection is intended to go to the shield
braid of the USB cable. This absorbs static electricity discharged
by humans using the front panel, and the shield braid also
reduces electromagnetic interference coming from the USB cable.
Now, on the Chaintech end, they have an "OverCurrent" function
on that pin. That is what OC2 stands for. The "#" means the
overcurrent function is active low, active when the pin is
grounded. If you connect the Bay One to the header, the GND
on the Bay One will make the overcurrent signal active, and
that will cause the Chaintech end to turn off power to the
USB header! Definitely a futile situation.
To fix this, one workaround is to pull the pin and wire
from the pin 10 GND. That is the GND that would go to
the OC2# signal if we just plugged in the Bay One USB cable. To
see how to pull a wire and pin from the Bay One cable end,
see "RELEASE-ABLE WIRE ASSEMBLY" at the bottom of this page:
<a style='text-decoration: underline;' href="http://www.frontx.com/head_con.html" target="_blank">http://www.frontx.com/head_con.html</a>
Using an Xacto knife tip, you can lift the plastic tab and
that should allow a single wire and pin to be extracted.
Now, what can you do with that GND pin which is now loose ?
If another unused USB header was close to the one you were
planning on using, you might plug the GND pin and wire onto
a GND pin from that header. Be careful not to short anything
else. If there is nothing "within reach", then simply wrap the
pin with electrical tape, to insulate it, so it does not short
to anything else on the motherboard. (For USB to work, at a
minimum you must wire the four adjacent VCC, TD-, TD+, GND
signals, to get a port to work.)
Now, something to know about USB headers and this overcurrent
function. USB jacks are intended to supply no more than 500mA
(half an amp) of current on the VCC +5V pin. On motherboards
that have a polyfuse to protect the USB port, generally you
will not find an OC pin on the header. If the USB port shorts
the +5V supply by accident, the polyfuse temporarily opens
and prevents damage. When the polyfuse cools down again, it
closes and the port returns to a working state.
On motherboards without fuses, it is the responsibility of
the header, to signal to the motherboard when there is an
overload. The motherboard uses a transistor to shut off current
to the header. As Chaintech has an OC pin on the header, it
implies they don't have a fuse in the path. (I don't know if
these options are all described in a USB standard somewhere or
not.) Just another nagging worry...
As you can see, doing front panel connections on a computer,
is a "non-standard zoo". The frontx.com web site has a lot
of info on how to make front panel interfaces for a computer,
but their products are a pretty expensive route to take.
Bottom line is, if there is anything on one of these devices
that makes you uncomfortable (like you don't feel you know
what you are doing), then better to leave it alone than bust
something. There are external card reader devices available
that just plug into a USB port on the back of the computer,
and that takes the uncertainty out of wiring them up. Similarly,
the audio jacks on the back of the computer work just fine for
connecting microphones, headphones, speakers and so on. There
is no absolute need to go near the headers on the motherboard,
unless you feel confident in what you are doing. I'm not mentioning
all this to scare you away from your project, but just to
help you decide whether this project is something you can handle
or not - I have a bad habit of assuming the people I help, know
everything I know, and I tend to forget that some people who
ask questions like this, know absolutely nothing about wiring
stuff up, and are intimidated by the prospect of having to mod
stuff.
HTH,
Paul<!-- ~MESSAGE_AFTER~ -->
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