Hey, Jay here. There is one component of the computer that you did
not replace and has to be constant the whole time. Even if you take
the MB out of the case you still have to plug up the POWER SWITCH to
it. If the power switch is flaky then you can lose power suddenly,
reboot, and cause hard crashes. On just about all PSUs if you just
kill the power like that with a short in a wire you will either have
to unplug the cord or reset the PSU(hold down the power button while
flipping the switch on the back to the - sign). Try replacing the
whole CASE with a brand new Antec PSU and see what happens.
Hi, I have had a look through this thread but no one seems to have
mentioned the CMOS battery.
I had a brand new motherboard that had these exact symptoms, I tried
everything but nothing made a difference not even buying a top of the
range 'PC power and cooling' power supply rated for huge servers.
I was so sure it was a power issue that I didn't bother checking the
CMOS battery, it was brand new motherboard so the battery had to be
fine...
Sure enough the battery was low (but not that low) and replacing it
cured the problem completely just like that.
It was a co-worker that suggested changing it BTW, I probably would
have never even checked it left to myself and would have probably sent
the board back.
It doesn't seem to be an uncommon problem either after asking people I
know, although most motherboards just forget their settings at every
boot rather than just re-setting randomly.
Best of luck with it,
-Jon
~~~~~~The following problem has confounded every IT friend and support person i
have presented it to and appears to defy logic so i am throwing it to a
broader audience of experts to see if it elicits some ideas. Thanks in
advance for considering it and apologies for cross-group posting!
Problem: Spontaneous power-offs that take place between 15 seconds and 30
minutes after booting. As if the power cord was yanked out of the back.
Green M/B LED remains on, power cord has to be disconnected for several
seconds before re-boot can take place.
PC background: home-built 18 months ago, ran fine until last week. I have
been building PCs for 15 years and have spent the last week running through
every permutation of test i can think of, to no avail.
Components tested (all of which have, in every configuration, replicated the
problem):
M/B
Asus a7v333 latest bios
Asus a7v8x-x v06 bios - rejects flash to latest 08 bios
temp problem? No. M/B temp under 35 degrees c at time of power-down (have
been staring at PC probe's temp montitor as it has gone down on 2 occasions.
Immediate boot-ups after power-down reveal no discrepancies in bios-based
temp monitor i.e. also reports 35 degrees c or under)
CPU
AMD Athlon 2100+
AMD Athlon 2500+
temp problem? No CPU temp under 40 degrees c at time of power-down (have
been staring at PC probe's temp montitor as it has gone down on 2 occasions.
Immediate boot-ups after power-down reveal no discrepancies in bios-based
temp monitor i.e. also reports 40 degrees c or under). Bios-based
auto-shutdown set at 95 degrees c
HD
8GB Seagate- freshly fdisked/formatted but fails to complete winXp install
(lasts between 15mins and 25 mins) before powering off
20GB IBM- Win98SE - exhibits power-down symptoms every time, works fine on
other machines. Lasts the longest time, up to 30 mins, running in 640x480
res
80GB Maxtor - Win Xp Home - lasts the shortest time, rarely more than 15
minutes, power-offs can happen without any apps running but tends to happen
within a few seconds of 3Dmark03 running and within 15 minutes of Norton
AV2K4 running
Software problem? No. problem replicated with winxp install on fresh disk.
Also run each HD in isolation to others, i.e. with no other no HD IDE/power
connections
Graphics
Radeon 9800pro - exhibits power-down symptoms every time, works fine on
other machines
Radeon 9700 Pro exhibits power-down symptoms every time, works fine on other
machines
GeForce Ti4600 - exhibits power-down symptoms every time, works fine on
other machines
Graphics card problem? maybe, but three different cards have replicated the
problem. Run with default VGA drivers and latest drivers
Memory
512Mb PC2700 Apacer CL2.5
512MB PC3200 Infineon CL 2.5
Memory problem? maybe, replicated with both DIMMS though. Could it be a
voltage issue? everything set to default in bios and no voltage setting
tampered with at any stage.
PSU
300W unbranded, came with case
400W high quality, multi-fan
Power problem? Dont know. the brand new 400w PSU immediately replicated the
problem. Have tried 4 different power cords in two houses on 5 different
sockets (!). All replicated the problem.
Others:
case - generic, have tried running the pc out of the case without any case
jumper connections or any other connections other than PSU housing, using
screwdriver to boot.
CD, DVD, Floppy, Soundcard, USB expansion card, game card expansion, other
USB connections - taken out/disonnected (ide, power etc) but problem still
exists
I have even tried, once an app is running, diconnecting mouse, keyboard and
monitor (!!) with the problem still taking place.
I have effectively changed PC entirely with these tests and still get this
problem!
One idea that was thrown out was a bios-residing virus. is there such a
thing (i cannot find mention of one anywhere let alone scanning or removal
methods)?
Does anyone have any other ideas?
Any help very much appreciated
Nick
ps Please post reply (e-mail address is false)
battery on both mbs appear fine. one is brand new.
Have you tried downloading distro of linux Knoppix for example thatNick G said:The following problem has confounded every IT friend and support person i
have presented it to and appears to defy logic so i am throwing it to a
broader audience of experts to see if it elicits some ideas. Thanks in
advance for considering it and apologies for cross-group posting!
Problem: Spontaneous power-offs that take place between 15 seconds and 30
minutes after booting. As if the power cord was yanked out of the back.
Green M/B LED remains on, power cord has to be disconnected for several
seconds before re-boot can take place.
PC background: home-built 18 months ago, ran fine until last week. I have
been building PCs for 15 years and have spent the last week running through
every permutation of test i can think of, to no avail.
Components tested (all of which have, in every configuration, replicated the
problem):
M/B
Asus a7v333 latest bios
Asus a7v8x-x v06 bios - rejects flash to latest 08 bios
temp problem? No. M/B temp under 35 degrees c at time of power-down (have
been staring at PC probe's temp montitor as it has gone down on 2 occasions.
Immediate boot-ups after power-down reveal no discrepancies in bios-based
temp monitor i.e. also reports 35 degrees c or under)
CPU
AMD Athlon 2100+
AMD Athlon 2500+
temp problem? No CPU temp under 40 degrees c at time of power-down (have
been staring at PC probe's temp montitor as it has gone down on 2 occasions.
Immediate boot-ups after power-down reveal no discrepancies in bios-based
temp monitor i.e. also reports 40 degrees c or under). Bios-based
auto-shutdown set at 95 degrees c
HD
8GB Seagate- freshly fdisked/formatted but fails to complete winXp install
(lasts between 15mins and 25 mins) before powering off
20GB IBM- Win98SE - exhibits power-down symptoms every time, works fine on
other machines. Lasts the longest time, up to 30 mins, running in 640x480
res
80GB Maxtor - Win Xp Home - lasts the shortest time, rarely more than 15
minutes, power-offs can happen without any apps running but tends to happen
within a few seconds of 3Dmark03 running and within 15 minutes of Norton
AV2K4 running
Software problem? No. problem replicated with winxp install on fresh disk.
Also run each HD in isolation to others, i.e. with no other no HD IDE/power
connections
Graphics
Radeon 9800pro - exhibits power-down symptoms every time, works fine on
other machines
Radeon 9700 Pro exhibits power-down symptoms every time, works fine on other
machines
GeForce Ti4600 - exhibits power-down symptoms every time, works fine on
other machines
Graphics card problem? maybe, but three different cards have replicated the
problem. Run with default VGA drivers and latest drivers
Memory
512Mb PC2700 Apacer CL2.5
512MB PC3200 Infineon CL 2.5
Memory problem? maybe, replicated with both DIMMS though. Could it be a
voltage issue? everything set to default in bios and no voltage setting
tampered with at any stage.
PSU
300W unbranded, came with case
400W high quality, multi-fan
Power problem? Dont know. the brand new 400w PSU immediately replicated the
problem. Have tried 4 different power cords in two houses on 5 different
sockets (!). All replicated the problem.
Others:
case - generic, have tried running the pc out of the case without any case
jumper connections or any other connections other than PSU housing, using
screwdriver to boot.
CD, DVD, Floppy, Soundcard, USB expansion card, game card expansion, other
USB connections - taken out/disonnected (ide, power etc) but problem still
exists
I have even tried, once an app is running, diconnecting mouse, keyboard and
monitor (!!) with the problem still taking place.
I have effectively changed PC entirely with these tests and still get this
problem!
One idea that was thrown out was a bios-residing virus. is there such a
thing (i cannot find mention of one anywhere let alone scanning or removal
methods)?
Does anyone have any other ideas?
Any help very much appreciated
Nick
ps Please post reply (e-mail address is false)
yes, but only in windows or during the install. it has yet to power
off whilst in the bios
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