Booger said:
Has anyone had a problem booting this machine?
If so, what problems cause this board not to boot? It seems to behave
normally, but with two different video cards, it does not post. No post
codes in speaker
M Black
Do fans spin or not ? Does the board stay powered, or does it
switch off in a matter of seconds ? Is the green LED on the motherboard
lit ?
Try starting the motherboard, by using a screwdriver tip to short
together the two pins where the power switch would normally go. That
will eliminate the case power switch as a problem. (Obviously, the
20 pin power cable has to be plugged in, and inserted far enough for
the latch on the connector to engage. You can damage the connector
if it isn't fully seated when power is flowing through it. Some
people don't press it in hard enough.)
Start the board and check the voltages. Using a disk drive power cable,
you can gain access to the +5V and +12V voltages. If your power supply
has a six pin cable (AUX power cable), there are some +3.3V pins on
there. Use a multimeter, connecting the black lead via an alligator
clip, to a lug on one of the connectors on the I/O area. This keeps
the black lead from shorting to something while you are working. The
red lead can then be used to probe the power connectors, to see if
the voltages are normal when the PSU is running and you see the fans
spinning. Evidence of +5VSB comes from the green LED on the motherboard
being lit. That should be enough voltages to get the board to boot -
the negative voltages may be used for the serial powers, but shouldn't
prevent POST.
An illegally keyed video card will prevent POST. The TYPEDET# pin
(A2) on the video card must be grounded, to pass the AGP_warn
detection circuit. The symptoms would be the motherboard just ignores
the power switch connected to the PANEL header - you press the power
button, but nothing happens. If your video card is a reasonably recent
4X or 8X video card, this shouldn't be your problem.
The processor has overheat protection via the COP circuit. It detects
the diode temp of the CPU, and shuts off power if the temp is too high.
The temp can be too high, if the heatsink/fan is missing, or even if
the heatsink is rotated 180 degrees from the proper position. (The
center of the heatsink doesn't line up with the silicon die, if the
heatsink is improperly rotated.)
There are plenty of things that can go wrong, so describing what is
working or not working for you, will help a bit. Take the motherboard
out of the computer case, and assemble it and the PSU on a tabletop.
Put a piece of cardboard under the motherboard, to prevent anything
from shorting to the bottom of it. I use a telephone book underneath
it, so that when the AGP video card is installed, the tip of the
faceplate of the video card has clearance to hang down. (I have an
A7N8X-E on the table in front of me, as I type this.)
You don't say whether this is the Deluxe board or not, as some
of the Asus boards have Voice POST, and with the Voice POST, you
can start with an empty board, and add components one at a time,
listening to the Voice POST message after each one is added.
Turn off the PSU via the switch on the back of the PSU, before
adding or removing any hardware - the green LED on the motherboard
has to be off, before you can touch anything. If doing the cardboard
test on the tabletop, be expecially careful not to jiggle the video
card while power is applied. If you need to disconnect the monitor,
power down the motherboard before trying it. And, before powering up,
each time, make sure the video card is fully seated in the slot.
Failure to check this, could result in a destroyed video card or
AGP slot.
HTH,
Paul
