Specs
http://www.foxconnchannel.com/en-us/product/Motherboards/detail_spec.aspx?ID=en-gb0000169
Picture
http://www.foxconnchannel.com/EN-US/Upload/Mainboard/200606090240000421_b_m_K7V600A-FRS.jpg
It is a KT600/VT8237 motherboard for S462 processors.
The AGP slot is keyed for 1.5V, implying it always runs at 1.5V. That
means, as far as the I/O voltage regulator is concerned, it only
has to support one voltage, which is 1.5V. And that means the interface
won't be paying attention to the TYPEDET# pin. (On universal AGP,
TYPEDET# would be grounded by the video card, as a way for the
video card to say "I prefer 1.5V". And that can be tied into the
linear regulator. But I think the slot on this motherboard,
should be 1.5V all the time.)
http://www.playtool.com/pages/agpcompat/agpslots.gif (yours is second
one down)
You'd have to get a copy of the AGP spec, and examine the power
pins, to see a reason why it is frying cards. That would be, on
the assumption it is a power problem. An alternate explanation,
is the Northbridge AGP interface has failed, and perhaps
isn't getting power, and all the I/O pins are sitting at
ground potential. And perhaps shorting something out on the
video card, when it is present.
In my limited experience probing around the AGP slot, I
cannot say I really understood what the devices near the
slot were doing. In other words, the voltages I measured,
didn't add up, on MOSFETs and things.
There appears to be a linear regulator near the DIMM slots.
(8 pin DIP opamp plus two MOSFETs.)
Then, a linear regulator and a wide copper plane, feeding
the Northbridge. Perhaps that provides a Northbridge
core voltage or something. (8 pin DIP opamp plus one MOSFET.)
And that leaves the MOSFET near the faceplate end of the
AGP slot. But I don't see anything adjacent that appears
to be controlling it.
For AGP pinout, you can look here. PDF page 50. VDDQ1.5 would
be I/O power.
http://web.archive.org/web/20030314...m/technology/agp/downloads/agp30_final_10.pdf
For comparison, AGP20 spec is here. PDF page 231 shows
that VDDQ voltage level, reflects the kind of card plugged
in. A 3.3V I/O only card, has the I/O power signals labeled as
VDDQ3.3. But on your slot, the pins will be VDDQ1.5. The VCC3.3
power pins, are available to power core logic. The VDDQ are dynamic,
as a reflection of the various options for signal levels
on the AGP slot signal pins. VDDQ1.5 powering of signal pads,
handles both 1.5V and 0.8V signalling cases.
http://www.motherboards.org/files/techspecs/agp20.pdf
I have heard of cases, where the VDDQ voltage was out of spec,
but it was on a universal AGP slot. In that case, the video
card failed to pull down the TYPEDET# signal, according to
the method described in the AGP spec. The video card designer
placed a series resistor on the ground connection. That
causes TYPEDET# on the video card, to rest at the wrong
level, and caused the AGP regulator to put out a bit
more than 2 volts. For a 1.5V card. Again, in your case,
the regulator should *not* be looking at TYPEDET#, because
it is only supposed to run at one voltage - and that is 1.5V.
Paul