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What does it mean when PC powers up as soon as power cord is plugged in? - Motherboard?

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SECTION25
 
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Default What does it mean when PC powers up as soon as power cord is plugged in? - Motherboard? - 11-08-2006 , 06:12 PM






Hi guys,

I have 2 pcs that I am having problems with.

The first one, when you plug in the power cord, powers up immediately.
It boots up fine, but if the power cord is removed, and plugged in
again, not only does it power up immediately, but the CMOS settings
seem to have been lost.

The pc is quite new, so I don't believe the CMOS battery has gone flat,
although I have not changed it. I think it has something to do with the
motherboard.

The other pc has a similar problem, where upon plugging in the power
cord it powers up immediately as per the other machine, but it does not
seem to boot at all. I have taken everything out to the point where it
is just the motherboard, CPU and PSU(even taken the RAM out to try to
get it to make beeps regarding that) Can't hear any warning tones,
although only the onboard motherboard speaker is being used (no pin
outs for an external speaker).

So I am at a loss.

In the case of the first motherboard I think something is all messed up
in the firmware or something like that.

And in the case of the second one, I think the motherboard might be dead


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Arno Wagner
 
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Default Re: What does it mean when PC powers up as soon as power cord is plugged in? - Motherboard? - 11-08-2006 , 06:19 PM






Previously SECTION25 <gibsandwich (AT) yahoo (DOT) com> wrote:
Quote:
Hi guys,

I have 2 pcs that I am having problems with.

The first one, when you plug in the power cord, powers up immediately.
It boots up fine, but if the power cord is removed, and plugged in
again, not only does it power up immediately, but the CMOS settings
seem to have been lost.

The pc is quite new, so I don't believe the CMOS battery has gone flat,
although I have not changed it. I think it has something to do with the
motherboard.
Power to the CMOS is part of the power-up/power-down circuitry.
It seems this circuitry is damaged in your case.

It may still be a flat battery and a default setting to power
on after AC loss in the BIOS. The health monitor in the BIOS
screen should show you the battery voltage. It is suposed to
be around 3.7V.

Quote:
The other pc has a similar problem, where upon plugging in the power
cord it powers up immediately as per the other machine, but it does not
seem to boot at all. I have taken everything out to the point where it
is just the motherboard, CPU and PSU(even taken the RAM out to try to
get it to make beeps regarding that) Can't hear any warning tones,
although only the onboard motherboard speaker is being used (no pin
outs for an external speaker).

So I am at a loss.

In the case of the first motherboard I think something is all messed up
in the firmware or something like that.
No, not firmware.

Quote:
And in the case of the second one, I think the motherboard might be dead
Agreed. Where did you get these boards?

Arno


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