Strange: PC Turns on, then off again

My wife has my old PC: Athlon 800, 256 MB SD-Ram, ASUS mobo, ATX.

Whenever I turn the powersupply ON (in back) the PC will sometimes turn
on, sometimes not. Other times, it will turn on for 2 seconds, sometimes
for 5 minutes. Then, suddenly, the power will go off. Never enough to
boot the OS (neither win, nor linux, nor a boot disk).

I have checked all the connections; and the powersupply and mobo and CPU
were all fine while they were installed in my PC.

I would like to avoid replacing *all* components, so I am hoping that
someone in this newsgroup might be able to diagnose where the problem is
likely originating from.

Any help is greatly appreciated.

PS. Sorry for x-post, but I'm trying to find the best neasgroup for this.
--

Regards,

Peter Reaper

-=-=-
The gargantuan size of SCO's lawsuit against IBM alone reminds me of the
old joke about the flea floating down the river on his back with a
hard-on, yelling "Raise the bridge!"
-=-=-

Start by learning what is happening. First collect facts.
A 3.5 digit multimeter (which is necessary for any serious
computer work anyway) is required. Monitor that purple power
wire from power supply to motherboard. It should be +5 volts
DC constantly. That is power to motherboard circuits that
control power supply. Now monitor green wire. 2.4+ volts
when power supply should be off. Less than 0.7 volts when
power supply should be on. What happens on purple and green
wires? Basic information necessary before anyone can answer
your question.

Peter Reaper wrote:
My wife has my old PC: Athlon 800, 256 MB SD-Ram, ASUS mobo, ATX.

Whenever I turn the powersupply ON (in back) the PC will sometimes
turn on, sometimes not. Other times, it will turn on for 2 seconds,
sometimes for 5 minutes. Then, suddenly, the power will go off.
Never enough to boot the OS (neither win, nor linux, nor a boot
disk).

I have checked all the connections; and the powersupply and mobo
and CPU were all fine while they were installed in my PC.

I would like to avoid replacing *all* components, so I am hoping
that someone in this newsgroup might be able to diagnose where the
problem is likely originating from.

Any help is greatly appreciated.

At the top of my list for what to try replacing first would be the power
supply.

--
DaveW



"Peter Reaper" wrote in message
...
My wife has my old PC: Athlon 800, 256 MB SD-Ram, ASUS mobo, ATX.

Whenever I turn the powersupply ON (in back) the PC will sometimes turn
on, sometimes not. Other times, it will turn on for 2 seconds, sometimes
for 5 minutes. Then, suddenly, the power will go off. Never enough to
boot the OS (neither win, nor linux, nor a boot disk).

I have checked all the connections; and the powersupply and mobo and CPU
were all fine while they were installed in my PC.

I would like to avoid replacing *all* components, so I am hoping that
someone in this newsgroup might be able to diagnose where the problem is
likely originating from.

Any help is greatly appreciated.

PS. Sorry for x-post, but I'm trying to find the best neasgroup for this.
--

Regards,

Peter Reaper

-=-=-
The gargantuan size of SCO's lawsuit against IBM alone reminds me of the
old joke about the flea floating down the river on his back with a
hard-on, yelling "Raise the bridge!"
-=-=-