power up the Mobo

ML wrote:
> I removed the cover of the PC casing to observe these:
>
> When I switch on the wall socket power, the motherboard's yellow color LED
> come on, the CPU fan spin a while then stop (2 times).
> Note that I have not press the power button on the casing.
> If I have not even press the power button on the casing, should I see these
> activities on the motherboard?
>
> The other problem is when I press the power button on the casing, the system
> power up but it dies down. I need to press the button a 2nd time in order to
> power up the system.
>
> Could the experts give some insight to these problems? Thank you.

The BIOS "Restore on AC Power Loss" setting could do it,
if you set that to [Power On]. The purpose of "Restore on AC POwer Loss",
is when you want a computer to reboot immediately after a power loss.
Then, every time the power is switched on at the back, the computer
will try to start.

If you press the power button, and the power dies down, and a second
press makes it work, a number of things could contribute to that.
A weak power supply might be one. Perhaps the motherboard has a
problem with its PS_ON# signal.

I have a motherboard here, that attempted to start up, without the
power button pressed, and the cause was an IDE cable that was half
inserted. If something upsets or stresses the Southbridge chip, such
as a half installed cable, that can result in PS_ON# being prematurely
turned on.

My guess would be, your problem is either a motherboard or a power
supply problem, but it would take more playing around to figure it
out. A question I would ask, is whether any of these symptoms were
similar when the computer was new. Did the computer ever "start twice"
in the past ? Some computers emulate the "Restore on AC Power Loss"
feature, by starting long enough for the BIOS to check whether the
user desired recovery after a power failure. So I have one computer
that starts for a few seconds only, when the power is switch on
at the back. But it has always done that, so there is nothing
abnormal in that case. It is just the nature of the design of
the motherboard.

If a standoff was installed in the wrong place, underneath the
motherboard, that can also cause premature starting of a computer.
Metal standoffs should only be installed, where there is a mating
"metal circle" on the bottom of the motherboard.

Paul

"ML" <ML DeleteThis @discussions.microsoft.com> wrote in message
news:97E40257-BCAA-493B-B1FA-4BCCBFA74F92@microsoft.com...

> The other problem is when I press the power button on the casing, the
system
> power up but it dies down. I need to press the button a 2nd time in order
to
> power up the system.
> Could the experts give some insight to these problems? Thank you.

MB power supplies fail almost as often as CD drives;
e.g. I have had to replace power supplies three times
since 1983, in a total of about seven PCs. This seems
average. It is one reason why power supplies are
manufactured as replaceable modules. They are cheap.

--
Don Phillipson
Carlsbad Springs
(Ottawa, Canada)

On Sun, 22 Jun 2008 03:49:01 -0700, ML <ML.DeleteThis@discussions.microsoft.com>
wrote:

>I removed the cover of the PC casing to observe these:
>
>When I switch on the wall socket power, the motherboard's yellow color LED
>come on, the CPU fan spin a while then stop (2 times).
>Note that I have not press the power button on the casing.
>If I have not even press the power button on the casing, should I see these
>activities on the motherboard?
>
>The other problem is when I press the power button on the casing, the system
>power up but it dies down. I need to press the button a 2nd time in order to
>power up the system.
>
>Could the experts give some insight to these problems? Thank you.
Why ask HERE? None of this has ANYTHING to do with XP (read the group
title).

Ask elsewhere

"Gurney" wrote:


>
> Ask elsewhere
>
Yes, I could go and ask elsewhere if only I have full internet access.
If I can't get the HW going, how am I suppose to use the OS?

I want to say thank you to those who gave suggestions on how to solve the
problem.

On Mon, 23 Jun 2008 06:19:02 -0700, ML <ML DeleteThis @discussions.microsoft.com>
wrote:

>
>
>"Gurney" wrote:
>
>
>>
>> Ask elsewhere
>>
>Yes, I could go and ask elsewhere if only I have full internet access.
>If I can't get the HW going, how am I suppose to use the OS?
>
>I want to say thank you to those who gave suggestions on how to solve the
>problem.

Well, you posted HERE meaning you DID have internet access. Ask here,
ask on a hardware group on the WWW - it's the SAME internet.

"Gurney" wrote:

> On Mon, 23 Jun 2008 06:19:02 -0700, ML <ML.DeleteThis@discussions.microsoft.com>
> wrote:
> >>
>> you posted HERE meaning you DID have internet access. Ask here,
> ask on a hardware group on the WWW - it's the SAME internet.
>

Sorry, I didnt make myself clear.
I have free limited internet access - can only access a few sites.
This is one of them.