A7V8X startup problem

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Ajax

I have an Asus A7V8X motherboard in a machine that is mostly used to
store backups from the other computers on my home network. It is
powered by a 350 watt power supply.

About a month ago, when booting, there were times when the monitor
was blank. I would perform a cold boot and the monitor would usually
come back on the first or second retry.

Last week no matter how many times I tried to restart the computer,
the monitor was blank. Suspecting a failing monitor, I connected
another monitor and it too was blank.

The video card is getting power. I took it out, cleaned the
connectors, and reinstalled it to no avail. I disconnected every
drive, except the boot drive (thinking that it might be a weak power
supply) - that did not help either.

When the computer is started, the boot drive spins up and everything
sounds normal, but there is no video and without a display, I can't
tell what is going on.

Any thoughts?
 
Ajax said:
I have an Asus A7V8X motherboard in a machine that is mostly used to
store backups from the other computers on my home network. It is
powered by a 350 watt power supply.

About a month ago, when booting, there were times when the monitor
was blank. I would perform a cold boot and the monitor would usually
come back on the first or second retry.

Last week no matter how many times I tried to restart the computer,
the monitor was blank. Suspecting a failing monitor, I connected
another monitor and it too was blank.

The video card is getting power. I took it out, cleaned the
connectors, and reinstalled it to no avail. I disconnected every
drive, except the boot drive (thinking that it might be a weak power
supply) - that did not help either.

When the computer is started, the boot drive spins up and everything
sounds normal, but there is no video and without a display, I can't
tell what is going on.

Any thoughts?
Click to expand...

If this is the A7V8X and not the A7V8X-X, you may have the
"Vocal POST" feature. Plug amplified speakers into the
green audio connector on the back of the computer. When
you turn on the computer, do you hear an error message
being played in the speakers ? (The error messages come
from the "Vocal POST" chip, and it can make sound, even
if a CPU is not plugged in. If you have a separate
sound card, the "Vocal POST" sound still will come
from the motherboard green audio connector.)

If you hear "System Failed CPU Test", visually inspect
the motherboard for bulging or leaking capacitors near
the CPU. These are cylindrical shaped devices, with a
plastic sleeve on the outside. The top has a stamping
in the metal, designed so that if the internal pressure
inside the capacitor gets too high, the metal bursts
open and relieves the pressure. That prevents the capacitor
from exploding like a fire cracker.

If there is a brown stain underneath the base of any
capacitor, that is another sign of the same problem.
The stain would be caused by leaking liquid from inside
the capacitor, that has dried onto the board.

Asus boards are usually pretty good with their caps, but
all caps eventually fail. The hotter the computer case
temperature, the less life the capacitor will have. A
contributing cause could be leaving the computer inside
a closet or inside a desk enclosure.

Another candidate to check would be the PSU. By your
description, it seems to be giving some power, but
maybe one of the rails is weak. ATX power supplies
can fail for the very same reason - capacitors or
other components that failed due to heat, age, or
bad design. If you have a multimeter, you could check
the output of the PSU while the machine is running.

HTH,
Paul
 
On Wed, 30 Nov 2005 17:35:59 GMT, (e-mail address removed) (Paul) wrote:

Thanks for the reply, Paul. I checked out the MB and found no
apparent physical damage. The video card didn't have any observable
damage either.

Taking the most obvious component as the likely culprit, I thought
that I would start by replacing the video card. After removing the
ASUS video card and installing a nVidia Geforce card the A7V8X is
running great.

It usually does not work out this easy. My old Biostar motherboard
failed with similar symptoms and its old video card is now running in
the A7V8X. Go figure.
 
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