On Sat, 14 Aug 2004 19:55:28 -0400, (Paul) wrote:

In article , awtwtw wrote:



As Dave said, the power supply is always a likely source of
failure to boot.

But, one of your other symptoms bothers me a bit. The red LED
on the motherboard is the "AGP_Warn" circuit. It is supposed
to check for an illegal 3.3V only video card, and prevent the
computer from starting. If an illegal (improperly keyed) video
card is present, the PS_ON# signal is prevented from reaching
the power supply, by AGP_Warn.

The AGP_Warn has two ingredients. One I have traced down, so
I know it is there. The TYPEDET# signal from pin A2 on the
video card is connected to one of the transistors. Apparently,
if TYPEDET# is grounded, everything is OK. If TYPEDET# floats,
then that will cause the red LED to light up.

A second ingredient of the check, is the circuit can only
stop the power, if an AGP card is inserted. It would be
inappropriate for the circuit to light the LED, if no video
card is present. So, to do its job, the logic has to be
AGP_Present AND TYPEDET#_floating. I don't know what pin is
checked to verify the card is present.

Now, your symptom of the LED flashing for a moment is weird.
The inputs to AGP_Warn are supposed to be static and unchanging.
Yet, your AGP_Warn lights for a moment and then stops, and
I cannot think of a mechanism for that to happen, unless +5VSB
is going out. And, you said the green LED on the motherboard
stays lit and the fan runs on the back of the case. That means
+5VSB is present and +12V is there to run the fan.

If you have another video card compatible with the board,
try swapping that in. It could be the video card, but as I
say, I cannot really think of a failure mechanism that would
cause the LED to light (indicating trouble) and then
extinguish, unless all power was being lost at the same time.

Paul

Firstly let me thank you for your detailed response. Most of this was
over my head but I understand the gist of it.

The power button on the front of the case will not turn the power off.
I have to hit the switch on the back.
I just tried it again and the red LED on the motherboard will not
flash at all.

I forgot that there is a voice "post reporter" at boot that may tell
me something. I didn't have the speakers on when this happened so I'm
going to try it.

So the power supply may be suspect even though it powers the other two
fans?
I don't have another video card but I have been leaning towards
getting another one.
Thanks again for your patience and time.