Franc Zabkar wrote:
On Fri, 26 Dec 2008 21:03:22 +0900, spodosaurus
put finger to keyboard and composed:

Hi all,

I have a problem that has only recently started (to my knowledge) and I
can't seem to solve it. I've got a P4 3.0GHz PC with an Asis P4P800S-X
board, 512mb RAM, Thermaltake 430W PSU and geforece fx5200 graphics. The
problem is that once the system is warm (and sometimes even from cold) a
shutdown then start gets the computer spinning its fans, powering off,
spinning fans, powering off, and repeating this cycle from 1-10+ times
before actually POSTing. Once it POSTs, it's all fine. Sometimes the
brief power ons result in the drives starting to power up as well, but
usually not. I've flashed the motherboard, replaced the PSU, cleaned and
reattached the HSF, and tried it with only CPU, GPU, RAM, and Video
attached to the motherboard without success in solving this issue. I've
come accross other accounts of similar issues, but they've usually been
solved by the steps I've already taken. Any ideas on where I could go
from here?
TIA,

Ari

It may be instructive if you can determine whether it is the
motherboard that is turning the PSU off in response to a fault
condition, or whether it is the PSU that is turning itself off in
response to a fault in the load. Or it may be that the motherboard is
resetting itself for some reason without turning off the PSU. To this
end it *might* help if you monitored the PS_ON signal (pin 14, green)
with a multimeter. A DMM may not detect rapid transitions on this pin,
though, even with a peak hold function.

See http://pinouts.ru/Power/atxpower_pinout.shtml

Does the PSU fan stop spinning, or is it only the motherboard fans
that do this?

PSU, CPU (connected to motherboard), and case fan (connected to molex
from PSU).


Have you tried replacing your graphics card with a low power PCI card?

- Franc Zabkar

This last suggestion got me thinking. I didn't recall this PC having
these problems before it was given to me. I thought it was using a
different graphics card and that I'd put the FX5200 in it (turns out the
actual card was the original geforce mx4000 after all). I tried putting
in a higher powered Radeon 9600 Pro card in there and turning it on from
cold - no joy, even though it always starts when it's at room
temperature after a few hours idle. So I popped in an old PCI card - and
it started immediately even though it had been running.

I'll update this if it starts having problems again in a few hours when
I restart it after it's been running a while.

Ari

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