This problem has baffled everyone...

On Tue, 10 Feb 2004 14:43:51 +0000 (UTC), "Nick G" ignore @ nospam.com
wrote:

snip

PSU
300W unbranded, came with case

You should've never even hooked this one up to a system, especially not
with any of the above video cards. Any number of components could be
damaged because of this power supply. We can hope that didn't happen.

I would tend to agree except that it ran fine with the 9800pro (most recent
addition) for around a month during which the card received intense use (no
o/cing i might add, just lots of games).

I don't think you understand. Not all damage is so immediate as, 1st try,
smoke pours out of box.



400W high quality, multi-fan

Not to be picky, but specific make/model is more useful than telling us,
"high quality, multi fan". For example, some people think Enermax is high
quality, but might not be adequate for the parts you've mentioned above,
due to insufficient 3V/5V rail capacity. I've even seen people claiming
that trashy power supplies, like Kingwin or Turbolink, were high quality.

the 400w PSU is made by Q-Tec and is not running the monitor (separate
power). It is the recommended PSU from Maplin (a specialist UK
tech/electronics components company). I dont think i need more than 400w as
i simply do not have enough components to require that power. however, i do
accept that given the symptoms it may well be that the psu or some other
power problem is at the root of this. The chances, however, of encountering
exactly the same problem with two different PSUs seems remote.

Q-Tec is NOT a high quality power supply.
Your system doesn't need 400W, but, the Q-Tec may not even be able to
supply 300W, regardless of it's labeling. Maplin likely recommends it
because it has the highest profit margin... Some 'sites sell 400W Q-Tec
for less than 1/3 the price of a 430W Antec... ever wonder why?

It's not at all unlikely that you're seeing the same problem from 2
different power supplies, if neither of them can adequate capacity to
supply enough power. You can stack up low (true) capacity power supplies
and see the same problem over and over again, it's not significant that
it's happened with two different units. I cannot be sure this (power
supply) is your problem, but now I certainly wouldn't assume it isn't the
power supply, would take a closer look at that possibility.

Actually, the need to pull the AC from a system usually IS a power supply
problem, either the unit itself or at least an indirect power supply
problem like a board shorting out, a fan shorting out, wires frayed
against a drive cage or similar power issue, where the power supply's
current or voltage monitoring senses the problem and shuts off the supply.

yes, but only in windows or during the install. it has yet to power off
whilst in the bios

Have you ever left it sitting in the bios for extended periods of time?
You might try that if not.

Hi,

Was unaware of the residual damage potential. Interesting, thought it does
not necessarily get me closer to id'ing the offending part:
However your PSU points are noted. I do actually suspect that it is
power-related and will have someone check the voltage tomorrow. Guess i
failed to see how a brand new PSU can fail to run what is a pretty ordinary
PC set up...
The bios runs fine for longer than any other configuration but i have not
left it going for over 45 mins or so. will test that now.
Many thanks
N

Q-Tec is NOT a high quality power supply.
Your system doesn't need 400W, but, the Q-Tec may not even be able to
supply 300W, regardless of it's labeling. Maplin likely recommends it
because it has the highest profit margin... Some 'sites sell 400W Q-Tec
for less than 1/3 the price of a 430W Antec... ever wonder why?

It's not at all unlikely that you're seeing the same problem from 2
different power supplies, if neither of them can adequate capacity to
supply enough power. You can stack up low (true) capacity power supplies
and see the same problem over and over again, it's not significant that
it's happened with two different units. I cannot be sure this (power
supply) is your problem, but now I certainly wouldn't assume it isn't the
power supply, would take a closer look at that possibility.

Actually, the need to pull the AC from a system usually IS a power supply
problem, either the unit itself or at least an indirect power supply
problem like a board shorting out, a fan shorting out, wires frayed
against a drive cage or similar power issue, where the power supply's
current or voltage monitoring senses the problem and shuts off the supply.

yes, but only in windows or during the install. it has yet to power off
whilst in the bios

Have you ever left it sitting in the bios for extended periods of time?
You might try that if not.

it appears to close down too quickly to generate a log (think power cord
yanked from the back of the PC).
Have it running on a surge protector and have not noticed any other
electricity supply problems to either houses it was tried in.


1. Have you looked in the event log to see if anything is reported? What
are the last few events in the applications and systems logs.

2. Have you tried running it on an UPS to eliminate any brown outs or
other
power anamolies. A good power supplie should filter most short dips, but
doesn't always happen in real life.

JT

Surge protectors will do nothing about drop outs, and after a few surges
are not effective on surges as well. Have seen some strange problems when
cheap surge protectors fail. An ups will prevent voltage drop outs at the
minimum. The better ones also add filtering and prevent overvoltages as
well.

Either way sounds like a power problem. Could be external, as in loose/bad
connection in surge protector, power cord, etc. Bad power to the wall
socket, etc.. Or interenal such as a bad PSU or a component/drive/fan/light
pulling too much power and causing the PSU to shut down due to the
overload.

JT

On Tue, 10 Feb 2004 16:04:52 +0000 (UTC), "Nick G" ignore @ nospam.com
wrote:

it appears to close down too quickly to generate a log (think power cord
yanked from the back of the PC).
Have it running on a surge protector and have not noticed any other
electricity supply problems to either houses it was tried in.


1. Have you looked in the event log to see if anything is reported? What
are the last few events in the applications and systems logs.

2. Have you tried running it on an UPS to eliminate any brown outs or
other
power anamolies. A good power supplie should filter most short dips, but
doesn't always happen in real life.

JT

In article m,
JT datacare@www wrote:
Surge protectors will do nothing about drop outs, and after a few surges
are not effective on surges as well. Have seen some strange problems when
cheap surge protectors fail. An ups will prevent voltage drop outs at the
minimum. The better ones also add filtering and prevent overvoltages as
well.

Either way sounds like a power problem. Could be external, as in loose/bad
connection in surge protector, power cord, etc. Bad power to the wall
socket, etc.. Or interenal such as a bad PSU or a component/drive/fan/light
pulling too much power and causing the PSU to shut down due to the
overload.

JT


If the OP has any computers in his house that _do_ work he can
prove/disprove the house power+surge protector hyphosis by running the
good computer from the receptacle while testing his parts.

Seems to me that you have to test by substitution, putting parts, one
at at a time, into a known-good system. Unique parts, like the mobo,
memory chips, and CPU, that can't be subsitiution-tested with the
resources available, just have to be tagged as questionable and put on
the shelf for another day.



On Tue, 10 Feb 2004 16:04:52 +0000 (UTC), "Nick G" ignore @ nospam.com




wrote:

it appears to close down too quickly to generate a log (think power cord
yanked from the back of the PC).
Have it running on a surge protector and have not noticed any other
electricity supply problems to either houses it was tried in.


1. Have you looked in the event log to see if anything is reported? What
are the last few events in the applications and systems logs.

2. Have you tried running it on an UPS to eliminate any brown outs or
other
power anamolies. A good power supplie should filter most short dips, but
doesn't always happen in real life.

JT




--
Al Dykes
-----------

kony wrote:
"Nick G" ignore @ nospam.com 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.

To clairify, every time it powers off, you MUST disconnect AC cord
(or flip PSU rear switch) to get it working again, you can't just
wait a few, say 3 minutes, and it'll come on again?

Wild guess - something is putting spikes on a power line and
triggering a crow-bar shutdown. At least it fits the facts.

--
Chuck F ) )
Available for consulting/temporary embedded and systems.
http://cbfalconer.home.att.net USE worldnet address!

It was tested in two different properties in different parts of London and
on multiple mains sockets. I am writing this in one of those properties and
on a working laptop which is being mains powered with no problems. The most
bizarre thing about this problem is that i have replaced every single major
component at least once if not twice and have still got the problem!

"Al Dykes" wrote in message
...
In article m,
JT datacare@www wrote:
Surge protectors will do nothing about drop outs, and after a few surges
are not effective on surges as well. Have seen some strange problems when
cheap surge protectors fail. An ups will prevent voltage drop outs at the
minimum. The better ones also add filtering and prevent overvoltages as
well.

Either way sounds like a power problem. Could be external, as in
loose/bad
connection in surge protector, power cord, etc. Bad power to the wall
socket, etc.. Or interenal such as a bad PSU or a
component/drive/fan/light
pulling too much power and causing the PSU to shut down due to the
overload.

JT


If the OP has any computers in his house that _do_ work he can
prove/disprove the house power+surge protector hyphosis by running the
good computer from the receptacle while testing his parts.

Seems to me that you have to test by substitution, putting parts, one
at at a time, into a known-good system. Unique parts, like the mobo,
memory chips, and CPU, that can't be subsitiution-tested with the
resources available, just have to be tagged as questionable and put on
the shelf for another day.

He means bad capacitors. Sometimes they go south and cause instability. Link
here -

http://www.motherboardrepair.com/

"Nick G" ignore @ nospam.com wrote in message
...
Bad Caps.
Can you expand on this?
thks
n

thanks. caps on both boards look fine. no leaks or discolouration.
"BigStan" wrote in message
...
He means bad capacitors. Sometimes they go south and cause instability.
Link
here -

http://www.motherboardrepair.com/

"Nick G" ignore @ nospam.com wrote in message
...
Bad Caps.
Can you expand on this?
thks
n

"Nick G" ignore @ nospam.com wrote in message ...
Thanks for your response. Answers/comments below:

the 400w PSU is made by Q-Tec and is not running the monitor (separate
power). It is the recommended PSU from Maplin (a specialist UK
tech/electronics components company). I dont think i need more than 400w as
i simply do not have enough components to require that power. however, i do
accept that given the symptoms it may well be that the psu or some other
power problem is at the root of this. The chances, however, of encountering
exactly the same problem with two different PSUs seems remote.


Can I just chip in here and suggest a different PSU as maplin know jack sh%# about
anything to do with computers. I have a variety of PSU units here that caused problems
similar to yours and two of them are newish Q Tec 400 watters.

You can get a resonable 400 watt unit made by Nexus from Novatec for 55 quid.
--
Mantric