Asus A8N-SLI Deluxe problem

  • Thread starter Thread starter Kevin M
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Kevin M

I just finished building a system as followes:
Asus A8N-SLI Deluxe
AMD 3000 64 bit processor
80 gb IDE HD
512 Cosair PC3200 RAM
Lite-on dvd-rw
Antec TP II 550 Power Supply.

All went well at first. Installed WinXP, AntiVirus, divers, etc. Used PC for
approx. 30 minutes and all of a sudden, the PC shut off. If I try to reboot,
it cuts off about 3 seconds after pressing the power button. Please help.

Thanks so much,
 
"Kevin M" said:
I just finished building a system as followes:
Asus A8N-SLI Deluxe
AMD 3000 64 bit processor
80 gb IDE HD
512 Cosair PC3200 RAM
Lite-on dvd-rw
Antec TP II 550 Power Supply.

All went well at first. Installed WinXP, AntiVirus, divers, etc. Used PC for
approx. 30 minutes and all of a sudden, the PC shut off. If I try to reboot,
it cuts off about 3 seconds after pressing the power button. Please help.

Thanks so much,
Click to expand...

Did the heat sink fall off ?
Got some thermal paste or a thermal pad on there ?

Have you checked temperatures in the hardware monitor page ?
(Assuming the computer stays on long enough to get in there.)

Athlon64 has a "thermtrip" feature just like the Intel P4.

Paul
 
The haet sink appears to be fine. Prior to any problems, the CPU temp was
around 42 Cel.

Thanks
 
Yes, it does have the thermal pad.

Thanks
Paul said:
Did the heat sink fall off ?
Got some thermal paste or a thermal pad on there ?

Have you checked temperatures in the hardware monitor page ?
(Assuming the computer stays on long enough to get in there.)

Athlon64 has a "thermtrip" feature just like the Intel P4.

Paul
Click to expand...
 
"Kevin M" said:
The haet sink appears to be fine. Prior to any problems, the CPU temp was
around 42 Cel.

Thanks
Click to expand...

There is a four second time constant associated with turning
off the computer with the power button. A long time constant
is used, to prevent accidental switch off. Could it be that
the switch is stuck or something ? I can never be certain
how the logic responds on these chipsets, to a stuck button.
I don't know if the time constant is ignored if the button
is stuck, or the time constant still fires four seconds
later.

Try unplugging the power switch. Then, _carefully_, use a
screwdriver tip to momentarily short together the two
power pins on the PANEL header. That will simulate what
the power switch would normally do. If the computer stays on,
then you have a defective power switch. (Alternately, you
can substitute the reset switch in place of the power switch,
and test with that. That is a bit safer than using the
screwdriver. The screwdriver is better for wnen you are
doing a "cardboard" test outside the computer case.)

The other possibility, is the power supply is bad, or it is
the combination of this motherboard and an Antec supply that
is not working out. Since you had it working, and the thing
is a 550W supply, I wouldn't think this is too likely.

Watch the green LED on the motherboard, as you switch on
the computer. The LED should be lit before you push the button
on the front of the computer case, and there should be no
flashing or glitching of the LED at the instant the computer
switches off. If the LED goes off for an instant, that means
+5VSB disappeared for some reason. The instant that the PSU
stops delivering +5VSB to the motherboard (and the green LED
goes off), the PS_ON# signal will get turned off, and then
the PSU will be switched off. In this case, the hypothesis
is that the +5VSB output of the supply is overloaded, and
the PSU kills the +5VSB when the internal regulator circuit
overheats.

Paul
 
Update:
I cleared or reset the CMOS settings for the second time, and now the PC
stays on but it does not post and there is no ouput to the screen. I have
tried removing all the devices, I've tried a different Power Supply. I'm to
the point to where I think I have a defective board or processor. I just
have no way to determine which.

Thanks
 
Kevin said:
I just finished building a system as followes:
Asus A8N-SLI Deluxe
AMD 3000 64 bit processor
80 gb IDE HD
512 Cosair PC3200 RAM
Lite-on dvd-rw
Antec TP II 550 Power Supply.

All went well at first. Installed WinXP, AntiVirus, divers, etc. Used
PC for approx. 30 minutes and all of a sudden, the PC shut off. If I
try to reboot, it cuts off about 3 seconds after pressing the power
button. Please help.
Thanks so much,
Click to expand...



Remove all hardware from the case. Set it up on a table. Do not place
hardware on anti-static bags. A piece of plywood works well enough.

Use just the CPU, video card, motherboard, PSU, and one DIMM. Does it boot ?
If so, start adding hardware. If not, reseat the existing hardware and try
again.


My guess is that something, probably the motherboard, is shorting to the
case.
 
OK. Removed everything from case. Still presents same symptoms. Even tried
without memory, video card and hard drive. It either comes on and shuts off
OR it stayes on but never posts.

Thanks again
 
"Kevin M" said:
OK. Removed everything from case. Still presents same symptoms. Even tried
without memory, video card and hard drive. It either comes on and shuts off
OR it stayes on but never posts.
Click to expand...

Is the ATX +12V 2x2 power cable securely in place ? The thing is,
the "shutting off" symptom could either be caused by the processor
sending "THERMTRIP" to the motherboard. Or, if the hardware logic
that controls PS_ON# is not receiving proper power, that can cause
the power to drop as well. Is the CPU fan connected to the CPU
fan header ? These kinds of problems could be caused by a bad
PSU or a bad motherboard. A cheap multimeter can be used to
measure the PSU output while driving the motherboard, and you
can then get a better idea of whether it is PSU related or
motherboard related. The Antec TP II will have two 12V output
circuits, so you would need to measure a signal from both of
them.

Some Asus motherboards have overcurrent protection in the Vcore
converter. Vcore is powered by the ATX +12V 2x2 power cable. If
the power supply is slow to provide energy to the board, the
Vcore regulator can recognize the funny behavior of the power
supply, as an overload condition. The regulator circuit may
have a "latch-off" feature, where for safety, the Vcore regulator
will then refuse to run, until you switch off the supply. Based
on the description of that algorithm, I think you can see you'll
get no where fast that way. (Some older regulators run in
"put-put" mode, where the regulator will retry, say once a
second, for maybe 50mS a try, until the overload goes away.
Such a regulator will burp several times, if connected to
a slow power supply, but the board will still POST.)

Try another brand of power supply, even if it is only a
350W with 20 pin connector. You should at least be able
to get into the BIOS that way, with minimal components
present.

With a bare motherboard and a PSU, does the board start when
you press the button, stay on for as long as you want, then
shut off after the power button is held in for four seconds ?
If it fails that test, then the CPU wasn't involved, and it
drops your culprits to motherboard and PSU.

Also, how is that fine Northbridge fan doing ? The first batches
of A8N-SLI had the unreliable 8000 RPM fan on them. If the
fan is stalled, the Nvidia single chip chipset can overheat.
I would expect the time constant to be a bit longer than
three seconds though. If, on the other hand, the heatsink
on the Northbridge is loose, an overheat condition could
occur pretty quick.

Just some guesses,
Paul
 
"Kevin M" said:
Thanks so much, I did try another (350) Enermax PS, but I got the same
results.
Click to expand...

Does the bare motherboard and the Enermax PSU work properly ?
Can you use the power button to turn the computer on and off ?
Does the Voice POST at least tell you "No CPU installed" ?

If the motherboard won't do that much, then it is RMA time
for the motherboard. You should be able to connect the bare
motherboard to the PSU and turn it on and off.

Paul
 
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