K8N Neo Platinum dead?

Question

I've had this K8N Neo Platinum for about two years now, have worked like a charm so far, but only so far. Few weeks ago, I updated my pc and the K8N was needed for a secondary comp. So I installed new sempron cpu, new rams and old GF6600 but it didn't boot. Speaker gives constant long beeps with breaks, like "beeeeeep......beeeeeep.....beeeeeep...." and the D-bracket hangs in "initializing keyboard controller" phase.
First I reseted the bios (all kind of power off), no effect. Still hangs the same way. Tried different ram (some bulk ddr400 and some slight better twinmos stuff. The very same twinmos-memories I tried, worked back in days 100% with this problematic mobo), no good. Then I thought that maybe the bios is too old to support sempron. I got my old AMD 64 3000+ cpu and tried to flash newer bios with that cpu, but no boot for me (reseted bios after every hardware change). Tried even with two different PSU's (both antec and the other one used to work this mobo, both work on different pc's), nothing.
The sempron and 64 cpu's both work on my different mobo (Abit NV8), all 4 memories work independently or in pairs as well on that NV8. Twinmos-rams were used with the K8N earlier. Both PSU's I tested, work on the other pc perfectly as well. I tried to boot with and without display card and ram, the result remains the same. Beeping and the same d-bracket code. (Only way to get the hangup in different phase is to remove CPU.) CPU-fan was connected. The board was removed from the case for tests and I tried with and without the front panel connectors (power switch, leds, speaker etc.) The 4pin ATX12V cable was connected, as was display card's external powercable.
List of hardware tried with that mobo, everything works with at least Abit NV8:
CPUs: AMD 64 3000+ (used to work with this K8N too) , AMD Sempron 2800+
RAM: Some bulk cheap low-quality 2x 512MB DDR400, Twinmos dual channel kit 2x 512MB DDR400 (something like that, worked with this "broken" mobo too back in days)
PSU: Antec Smartpower 350W, Antec Truepower 350W (the old PSU of that K8N-pc)
Graphics: Club3d GeForce 6600
I'm out of ideas currently. Is the board officially broken?

Answer 1

qalaksi - you said:
"Funny detail, which I forgot to mention in the original post, is that the the system power goes on instantly when I switch on the main switch behind the PSU."
Dumb question - is the power supply connector installed correctly?  I have seen some 20+4 connectors that can get installed the wrong way - reversed or a row or two offset.  Results are unpleasant to board.
Have you taken a close look at both sides of the board for foregin objects?  The power going on sounds like something is bridging the 'start' pins on the power connector (I don't remember which ones they are) or something else down the line - maybe the header where the power/reset switches connect or any trace related to these.  It is possible the board got some metal flakes or other conductive material on it - it might happen when screws are removed or from some other source.  Also can happen when semiconductors are fried internally, but then you have a dead horse.
I assume you have tried it completely stripped - CPU, one stick of RAM, very basic video card, nothing else (not even a kbd).  That should give you something on the screen if its little brains are coming up.
But - 'initializing KBD controller' is a nasty error code.  I have seen dead boards with this one going back many years to original PC.  The KBD controller, some variant of an 8048/8052, is a vulnerable part since it is connected to the outside world via KBD cable and a likely static entry path, esp. when mobo is air mounted w/o good local ground plane as it would have if mounted in a metal case.  Unless you can find some reversible FOD (foregin object damage) I would write this one off and move on to something else.  Too bad.
ss