Many connectors on case will not fit motherboard

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I have bought an Antec Titan 550 case

and a

Tyan Thunder K8WE (S2895) (dual Opteron) motherboard

Many of the connectors from the case will not fit the motherboard because the
keys are in the wrong place.

The Audio, USB and Firewall connectors are *all* affected. The USB looks totally
odd, with no resemblance of sense. The firewall and audio can be made to work by
moving a key around I think.


The motherboard uses a 10 pin header as follows.

1 = VCC   ;  2 = VCC
3 = DATA- ;  4 = DATA+
5 = DATA+ ;  6 = DATA+
7 = GND   ;  8 = GND
9 = key   ; 10 = GND

The cable from the case has a 10 pin header, but with a key in pin 1 and no
cable in pin 2. There are red cables on pins 9 and 10. So

a) A red cable on the connector goes to GND on the motherboard (odd use of a red
b) A red cable on the connector goes to a missing pin (key) on the motherboard.
c) The key on the cable in pin 1 prevents it going onto the header  where VCC
leaves the motherboard.

This seems *very* odd. This makes me think someone has wired the connector wrong.

Looking at the manual for the Antec Titan case:

the pin layouts are the same as the motherboard manual. So I think they are both
using the same standard which according to the manual on the case is an Intel

Hence I think someone has wired it all wrong.

Motherboard has a 14 pin header as follows:

  1 = NC   ;  2 = Key
  3 = TPA+ ;  4 = TPA -
  5 = GND  ;  6 = GND
  7 = TPB+ ;  8 = TPB -
  9 = +12V ; 10 = +12V
11 = GND  ; 12 = GND
13 = KEY  ; 14 = KEY

This means the outer 4 pins are not used, but the other 10 are all used,
although four of them are GND.

The case has a cable with a 10 pin connector (i.e. not 14 like the motherboard).
But pin 10 has a key in it. So this can *not* fit the motherboard in any way.

The manual on the case does show a 10 pin cable, whereas the motherboards manual
shows a 14 pin header. So they can't even agree on the number of pins there.

Front Panel Audio
The audio cable from the front panel has a 10 pin connector. The pinout is not
described in the manual on the case. There are in fact 8 or so single connectors
connected to this connector, so one can in principle connect it up any way one
wants using them.

The motherboard manual shows a layout like this:

1 = MIC_L         ;  2 = GND
3 = MIC_R         ;  4 = VCC-
7 = AUD_DET       ;  8 = key

The cable has a key on pin 4, so it it impossible to connet put the connector on
the header and pick up VCC-  (Quite why you would want to pick up VCC- is not
obvious to me. Would it ever be needed - perhaps for bias on microphones or
something ? ).

Dave K     MCSE.

MCSE = Minefield Consultant and Solitaire Expert.

Please note my email address changes periodically to avoid spam.
It is always of the form: month-year@domain. Hitting reply will work
for a couple of months only. Later set it manually.

Re: Many connectors on case will not fit motherboard wrote:

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work by
of a red
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are both
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motherboards manual
is not
way one
connector on

For what it is worth, I have a couple different models
of Antec cases with front panel wiring errors. In those
cases, the label on the wire does not correspond to the
correct pin on the connector.

One solution is to simply not bother connecting the
Antec wiring to your motherboard. Avoiding the Antec
wiring means not having to buzz out the wiring with
an ohmmeter, or reinvent the wheel.

For the USB pinout, there are a couple of slight variations
on the 2x5 pinout you show. Some motherboards have an
active low overcurrent signal, which is an input on the
motherboard. Motherboards which have a fuse onboard for the
USB power source don't need such a signal.

Having a red wire connected to a GND pin is obviously wrong.
Black is the color of GND and Red is +5V in this case. So you
know something bad is going on, and I would not connect their
USB cable if that is the case.

There really isn't a standard header pattern for Firewire.
Some motherboards use a single inline header 1xN, others use
2xN headers of various sizes. The pinout is sometimes optimized
for use with ribbon cable. Grounds are placed between the TPA and
TPB pairs as crosstalk spacers. A separate pair of grounds may
be used for the ground return of the Firewire cable power (VP and VG
are sometimes used as signal names). Due to the current carrying
capacity of header pins, it is a good idea to use two square
pins for VP and for VG (the names of +12V and +12V_return_wire
for powering Firewire).

Texas Instruments ( has some information on "galvanic
isolation" for Firewire. There is supposed to be a scheme to
avoid joining the grounds of Firewire equipped devices that
could have different ground potentials. Computer manufacturers
seem to ignore all advice of that sort, and on a computer Firewire
interface, the VG and GND are joined together. Since Firewire
"networking" is supposed to be supported by connecting two computers
together, computer design should really follow the rules. The Antec
wiring obviously falls into this camp of thought, by not identifying in
any meaningful way, what their GNDs are wired to.

(If you plan to use Firewire, plug your Firewire peripheral
into the same power strip as your computer, for least risk.
Another way to reduce risk, is use a 6 pin to 4 pin adapter,
and a 4 wire Firewire cable. The 4 pin Firewire connector carries
no cable power, and that makes it a lot safer to work with.
Disconnecting VP and VG at the motherboard is another way to
achieve the same effect (if you could figure out which pin is
which). The Firewire peripheral must be self-powered to work when
using the 4 pin type interface method. My experience with Firewire
enclosures, is they have a "sneak path" power wise, and the front
LED on one of my enclosures glows at half brilliance when the AC
switch on the back of the enclosure is switched off. That means
the enclosure is doing something nasty to the cable power, which is
not good for the motherboard, or for the adapter electronics inside
the enclosure. Firewire seems to be a crapfest when it comes to

This is an audio pinout from another motherboard.

                    MIC2 X   X AGND  
                  MICPWR X   X +5VA
              Line_out_R X   X BLINE_OUT_R  
                      NC X   X  
              Line_out_L X   X BLINE_OUT_L

On a stereo 1/8" plug, the terminal names are "Tip", "Ring", and
"Sleeve". On a stereo output, the corresponding wiring is
"Left", "Right", and "GND". On a mono microphone, the corresponding
wiring is "Mic", "Mic_power", "GND". On a stereo microphone,
the corresponding wiring would be "Mic_Left_plus_power",
"Mic_right_plus_power", and "GND".

Your Tyan header is correct, in the sense that the MIC2 pin above
is labelled as "Left" by Tyan. MICPWR is a voltage somewhat less
than 5V, with a series resistor of 2.2K ohms or so as a current
limiter. Mono electret microphones join Tip and Ring at the mic,
and when you speak into the mic, the mic modulates the voltage
at the end of the 2.2K resistor. If the Tyan header is actually
wired for stereo mic, then in fact both Tip and Ring get their
own private 2.2K resistor limited power feed, and both Tip and
Ring are separately modulated by the stereo microphone (like
an Andrea Superbeam microphone).

The +5VA signal shown above, is a "hard" source of +5V. It was
put in the Intel standard, as a power source for a headphone
amplifier mounted in the front of the computer case. I have
never seen mention of any computer case that comes with such an
amplifier, but I'm sure it must exist somewhere. There could be
dire consequences if you wire to that pin, as I'm not even
sure that pin is current limited by a fuse.

The Line_out_x and BLINE_OUT_x wiring, allows muting the rear
green speaker jack, when headphones are plugged into the front
of the computer case. Since you have enough wires on your Antec
case to hook up the Line_out_x and BLINE_OUT_x type wires, your
muting function is bound to work.

How do I feel about Antec wiring ?

1) _Always_ use an ohmmeter to verify the labelling of the wires.
   I suspect there are no electrical engineers working at Antec.

2) If Antec pisses you off enough, do what I did to my last
   build. Just rip the front connector assembly out of the
   case, and throw it in your junk pile. I got sick of looking
   at those wires dangling inside the case :-)

3) If the Antec wiring cannot be modified non-destructively to
   meet modern standards, one option is to phone their tech
   support and complain. In the case of their botched USB 1.1 only
   front panel wiring, they actually send customers replacement
   assemblies to fix their embarrassing mistakes. Maybe you'll
   get lucky, and they will have figured out by now, how wrong
   the Titan is. If you would rather avoid dealing with them,
   go to FrontX and make yourself a drive bay solution.


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