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Old February 10th 04, 02:15 PM
~misfit~
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Nick G wrote:
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)


Bad Caps.
--
~misfit~