Please help troubleshoot nonfunctional A7M266

[Ron Miller]

I have had a homebuilt A7M266 running smoothly with Windows XP for about
2.5 years. About 9 months ago, I upgraded the original CPU to a
Palomino-core XP 2100+. That went smoothly, and I never had one bit of
trouble with this machine until today.
My son was playing a flight sim, and the computer locked up. There was a
screen display, but no cursor movement or any input -- i.e., CTRL-ALT-DEL
did nothing.
I powered down manually and tried to immediately power up again.
- The fans run and both the power and HD LEDs illuminate on the front of
the case, the latter continuously, but there is no display at all, and the
LED on my monitor continues to blink rather than illuminate steadily as it
does when getting a VGA signal.
- Every fan in the computer is operating, including the CPU, northbridge,
and video card. The heatsink on the CPU and display adapter feel cool to
the touch.
- I cannot tell if the HDs are running or not. They're cool, and I don't
feel vibration in any of the three.
- The power LED on the CD-RW lights, but not on the DVD burner. The trays
will not open on either optical drive.

1 -- I substituted an older nVidia-based AGP card for the GeForce 3, but
there was still no display whatsoever -- no video-card BIOS, no Asus logo,
nothing but a black screen
2 -- I shorted the RTC solder points to no avail.

With NO display at all and NO beeps, does this mean a dead CPU, dead BIOS,
or a dead MB?

Thanks,

 

[Paul]

I have had a homebuilt A7M266 running smoothly with Windows XP for about
2.5 years. About 9 months ago, I upgraded the original CPU to a
Palomino-core XP 2100+. That went smoothly, and I never had one bit of
trouble with this machine until today.
My son was playing a flight sim, and the computer locked up. There was a
screen display, but no cursor movement or any input -- i.e., CTRL-ALT-DEL
did nothing.
I powered down manually and tried to immediately power up again.
- The fans run and both the power and HD LEDs illuminate on the front of
the case, the latter continuously, but there is no display at all, and the
LED on my monitor continues to blink rather than illuminate steadily as it
does when getting a VGA signal.
- Every fan in the computer is operating, including the CPU, northbridge,
and video card. The heatsink on the CPU and display adapter feel cool to
the touch.
- I cannot tell if the HDs are running or not. They're cool, and I don't
feel vibration in any of the three.
- The power LED on the CD-RW lights, but not on the DVD burner. The trays
will not open on either optical drive.

1 -- I substituted an older nVidia-based AGP card for the GeForce 3, but
there was still no display whatsoever -- no video-card BIOS, no Asus logo,
nothing but a black screen
2 -- I shorted the RTC solder points to no avail.

With NO display at all and NO beeps, does this mean a dead CPU, dead BIOS,
or a dead MB?

Thanks,

Maybe one of the rails on the PS is dead. It sounds like +5VSB is ok,
because the rest of the supply won't start without that. Your +12V is
running, via the fans. But if +5V (the real +5 supply) is dead, that
might stop the drives from spinning. While the drive motor runs from
+12V, the logic board on the drive runs from +5V. If you have another
power supply, try swapping that first.

Otherwise, strip the machine a piece at a time, and see if it wakes
up. Remove the things that aren't essential first.

HTH,
Paul

 

[Ron Miller]

Maybe one of the rails on the PS is dead. It sounds like +5VSB is ok,
because the rest of the supply won't start without that. Your +12V is
running, via the fans. But if +5V (the real +5 supply) is dead, that
might stop the drives from spinning. While the drive motor runs from
+12V, the logic board on the drive runs from +5V. If you have another
power supply, try swapping that first.

Otherwise, strip the machine a piece at a time, and see if it wakes
up. Remove the things that aren't essential first.

HTH,
Paul

Thanks, Paul, but it was something relatively simple. I had pushed the
Reset switch on the front panel as soon as the computer originally crashed.
That little switch stuck in the "in" position, and that caused the symptoms
I described.
Unfortunately, in the few hours of troubleshooting before finding the
problem, I had cleared the CMOS, and a sad chain of events led to
corruption of the Master Boot Records or Partition Tables. I'm somehow up
and running again, but Norton Disk Doctor really messed me up. It offered
to fix the partitions on the second hard drive and in doing that actually
created a Primary partition the same size as the Extended partition that
was already there meaning that that 40GB drive had TWO 40GB partitions on
it. Thanks a bunch, Symantec!!! I had to use FDISK to delete the new
Primary partition. Things look copasetic now -- after EIGHT STRAIGHT HOURS
of troubleshooting all because of a switch that stuck and was too tiny for
it to be easily visible.

Ron

 

[Paul]

Thanks, Paul, but it was something relatively simple. I had pushed the
Reset switch on the front panel as soon as the computer originally crashed.
That little switch stuck in the "in" position, and that caused the symptoms
I described.
Unfortunately, in the few hours of troubleshooting before finding the
problem, I had cleared the CMOS, and a sad chain of events led to
corruption of the Master Boot Records or Partition Tables. I'm somehow up
and running again, but Norton Disk Doctor really messed me up. It offered
to fix the partitions on the second hard drive and in doing that actually
created a Primary partition the same size as the Extended partition that
was already there meaning that that 40GB drive had TWO 40GB partitions on
it. Thanks a bunch, Symantec!!! I had to use FDISK to delete the new
Primary partition. Things look copasetic now -- after EIGHT STRAIGHT HOURS
of troubleshooting all because of a switch that stuck and was too tiny for
it to be easily visible.

Ron

Ouch!

Paul