HD LED Cathode 1 o o 2 PS LED cathodeHD LED Cathode 1 o o 2 PS LED cathodeHD LED...

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I have a MOBO Asus P4SD made for Hewlett Packard that has a header
mapped out as follows:

HD LED Cathode  1  o  o 2   PS LED cathode
    HD LED Anode  3  o  o 4   PS LED anode
                   GND  5  o  o 6   PWR Btn
              M Reset  7  o  o 8   GND
               +5 VDC  9  o  o 10 NC
                    NC  11  o  o 12 GND
                  GRD  13  o
       Chassis ID2  15  o  o 16 +5 VDC
       Chassis ID0  17  o  o 18 Chassis ID1

I am not seen the terms cathode and anode applied in this scenario
before.  Is cathode - + and anode = -?

No idea what M Reset, NC, ID2, ID1, ID0 are.

How careful should I be connecting these pins to connectors from my
Is the PWR button and the opposite GND what I am used to as the POWER

Any help here is appreciated.



Need Help connecting up a MOBO

Sorry for prior post

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Re: Need Help connecting up a MOBO

Jethro wrote:
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The mechanism I use to remember cathodes and anodes, is the letter
A for Anode, fits in the triangle on the diode symbol. To be forward
biased and light up, the Anode must be more positive than the Cathode.

       (+)      |\ |     (-)
          Anode | \| Cathode
       ---------|  |------
                | /|
                |/ |

There is a more technical definition here, suitable for settling bets
while you're drinking :-)


Having tried to look up some info on HP's scheme within the last
day, it looks like the plugs could go something like this.

         HD LED ___/ 1  o  o 2  \___ Power LED
                   \ 3  o  o 4  /
         Reset  ___/ 5  o  o 6  \___ Power
         Switch    \ 7  o  o 8  /    Switch

As far as damaging it, by putting the plugs on the
wrong pins, I would think those 8 pins are pretty
immune to mistakes. The LED path should have current limiting
resistors. The logic signals on the reset and power switches have
pullup resistors, that will limit the current. When I look at
your header diagram, the part that scares me most, is seeing
signals that look like raw "+5VDC" on the header. Unless those
are protected by 1 amp Polyfuses, there is room for some mischief
there if you aren't careful. But pins 1 thru 8 look pretty safe.

It is anyone's guess, what function pins 9 thru 18 are intended for.


Re: HD LED Cathode 1 o o 2 PS LED cathodeHD LED Cathode 1 o o 2 PS LED cathodeHD LED Cathode 1 o o 2 PS LED cathodeHD LED Cathode 1 o o 2 PS LED cathode

On Mon, 09 Apr 2007 23:24:51 GMT, Jethro

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Anode and cathode are terms describing the parts inside the
LED.  Anode is positive, cathode negative.  If you look
carefully at an LED (one that is clear so you can see
inside), the cathode is the lead with the dish shaped
termination on it.  See picture;

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I'd guess it's just the reset switch (7-8), (N)o
(C)onnection, and the others aren't applicable, maybe one
pair was for a case intrusion switch.

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Medium?  It wasn't an answerable question.
It won't kill anyone if wrong, but you don't want to be
hooking up anything to the 5V, nor doing anything except
hooking it up as it's expected to be, until you have a
reason to deviate from that and know what/why/etc.

If you hooked up power switch reversed, it still works (it
isn't polarized).  Same with reset.  LEDs if reversed just
won't light up, but wouldn't be damanged.  Don't hook
anything up to the other unknown or 5V pins without reason.

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yes that'll work, or any other gnd if not the one directly
across from it.

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