Motherboard Won't Boot

[Guest]

Archived from groups: microsoft.public.windowsxp.hardware (More info?)

I'm working to resolve a strange problem.

The initial problem with this computer several weeks ago was a defective 250
watt power supply. I replaced that and everything seemed ok. The users had
no further trouble with the system until last week when the screen went
blank while the user was online. From then on, the user could not get the
computer to boot up.

I'm not referring to a BSOD situation; that would actually represent an
improvement over the computer's current situation. The computer simply won't
boot even though the Power light and the red disk activity light turn on
when we press the power button. That is, the computer does not issue the
usual beep after we press the power button, and it displays absolutely
nothing on the monitor. The red disk activity light remains on solid along
with the green power light until I unplug the computer. It will not even
power down when we press and hold the Power button for a looooong time; much
longer than the few seconds it should take to power the computer down.

I tried replacing the Pentium III 450 MHz processor with another one, but
that made no difference whatsoever. I reseated all of the connectors as
well as the two SDRAM sticks. That made no difference either. So, I
finally REPLACED the MOTHERBOARD. However, the computer STILL refuses to
boot up. It continues to do exactly the same thing that I've described
above. And, I've ruled out the possibility of anything being caught between
the motherboard and metal cabinet.

Is it possible that a defective hard disk could actually keep a motherboard
from performing its initial startup process? If not, I'd very much
appreciate your help in determining what's wrong with this system. I've
built and repaired several dozen computers, but I haven't run into anything
like this until now.

This computer is an ATX clone with an ASUS P3B-F motherboard, with a Pentium
III 450 MHz processor, 128mb SDRAM, a 40gb Western Digital hard drive,
3-1/2" floppy, and CD-ROM drive.

--
With kindest regards,

Dick Smith
SmithRMS@Comcast.net

 

[bar]

Archived from groups: microsoft.public.windowsxp.hardware (More info?)

If you want to spend a lot of time 'chasing' down the fault, well and good,
however it may be cheaper to buy a new system [PC case only, not mouse,
keyboard and screen].

To track down the problems, first eliminate as many 'variables'. So, unplug
the mains plug and open up the PC.

Unplug all the interface cables from the motherboard [IDE and Floppy]:
remove any PCI cards [except video if it is PCI]: remove all but one memory
module: if there are any others sch as a USB header plug, take them off also.

Now with a 'barebones' motherbard you can try to get into BIOS.

If the system won't pwer up, you have either:
1. Faulty Power Supply
2. Faulty CPU or CPU Fan
3. Faulty Motherboard

You can check these out in the following sequence: reboot after each step,
but only do one thing at a time:

1. by swapping with another working one in another PC.
2. change CPU, and then after a reboot change the fan
3. replace the Mobo

If at any time you have regained the ability to get to BIOS, then one by
one, add back the items 'unplugeed' from the Mobo and reboot. If it fails to
boot at any time, then consider that you have identified the faulty component.

By this time it would be cheaper to buy a new box! Labour costs make PC
diagnostics and repair very expensive.


"" AA Smith"" wrote:

> I'm working to resolve a strange problem.
>
> The initial problem with this computer several weeks ago was a defective 250
> watt power supply. I replaced that and everything seemed ok. The users had
> no further trouble with the system until last week when the screen went
> blank while the user was online. From then on, the user could not get the
> computer to boot up.
>
> I'm not referring to a BSOD situation; that would actually represent an
> improvement over the computer's current situation. The computer simply won't
> boot even though the Power light and the red disk activity light turn on
> when we press the power button. That is, the computer does not issue the
> usual beep after we press the power button, and it displays absolutely
> nothing on the monitor. The red disk activity light remains on solid along
> with the green power light until I unplug the computer. It will not even
> power down when we press and hold the Power button for a looooong time; much
> longer than the few seconds it should take to power the computer down.
>
> I tried replacing the Pentium III 450 MHz processor with another one, but
> that made no difference whatsoever. I reseated all of the connectors as
> well as the two SDRAM sticks. That made no difference either. So, I
> finally REPLACED the MOTHERBOARD. However, the computer STILL refuses to
> boot up. It continues to do exactly the same thing that I've described
> above. And, I've ruled out the possibility of anything being caught between
> the motherboard and metal cabinet.
>
> Is it possible that a defective hard disk could actually keep a motherboard
> from performing its initial startup process? If not, I'd very much
> appreciate your help in determining what's wrong with this system. I've
> built and repaired several dozen computers, but I haven't run into anything
> like this until now.
>
> This computer is an ATX clone with an ASUS P3B-F motherboard, with a Pentium
> III 450 MHz processor, 128mb SDRAM, a 40gb Western Digital hard drive,
> 3-1/2" floppy, and CD-ROM drive.
>
> --
> With kindest regards,
>
> Dick Smith
> SmithRMS@Comcast.net
>
>
>

 

[Andy]

Archived from groups: microsoft.public.windowsxp.hardware (More info?)

Mr. Smith:

Bar has done an excellent job describing a solid touble shooting
technique. He pointed out the key reasons why a pc will not boot. You simply
are not getting power. your mother board notices that the cpu or cpu fan is
faulty and will not power to keep from damaging the components further or
your motherboard is faulty. That really seems to me to be the logical
reasons. I have had a pc not turn before on me. I could not figure out why. I
simply disconnect all connections on the motherboard and plugged them all
back in and it solved the problem. I still to this day do not know exactly
what the culprit was but I am thinking my power/reset button on the case may
have worked itself loose. My suggestion would be to test those first. Swap
your power supply that you just put in the computer into another known
working computer to see if you have a power supply that was DOA, it happens.
Follow Bars advice and you are for sure going to isolate the defictive
component. Good luck!

 

[Guest]

Archived from groups: microsoft.public.windowsxp.hardware (More info?)

" AA Smith" wrote:

> I'm working to resolve a strange problem.
>
> The initial problem with this computer several weeks ago was a defective 250
> watt power supply. I replaced that and everything seemed ok. The users had
> no further trouble with the system until last week when the screen went
> blank while the user was online. From then on, the user could not get the
> computer to boot up.
>
> I'm not referring to a BSOD situation; that would actually represent an
> improvement over the computer's current situation. The computer simply won't
> boot even though the Power light and the red disk activity light turn on
> when we press the power button. That is, the computer does not issue the
> usual beep after we press the power button, and it displays absolutely
> nothing on the monitor. The red disk activity light remains on solid along
> with the green power light until I unplug the computer. It will not even
> power down when we press and hold the Power button for a looooong time; much
> longer than the few seconds it should take to power the computer down.

There's your best clue. AFAIK there's only two things that can cause an
Asus 440BX chipset motherboard to retain power like that:

1. Reset switch jammed on or shorted. Try disconnecting it at the
motherboard header.

2. Dead hardware monitoring (Winbond) chip on the motherboard. Since
you've swapped motherboards, this is less likely unless an electrical
fault is taking out the chip - most likely culprit is a 3-wire fan with
an internal failure that causes it to send +12v on it's tachometer output.

HTH

P2B

> I tried replacing the Pentium III 450 MHz processor with another one, but
> that made no difference whatsoever. I reseated all of the connectors as
> well as the two SDRAM sticks. That made no difference either. So, I
> finally REPLACED the MOTHERBOARD. However, the computer STILL refuses to
> boot up. It continues to do exactly the same thing that I've described
> above. And, I've ruled out the possibility of anything being caught between
> the motherboard and metal cabinet.
>
> Is it possible that a defective hard disk could actually keep a motherboard
> from performing its initial startup process? If not, I'd very much
> appreciate your help in determining what's wrong with this system. I've
> built and repaired several dozen computers, but I haven't run into anything
> like this until now.
>
> This computer is an ATX clone with an ASUS P3B-F motherboard, with a Pentium
> III 450 MHz processor, 128mb SDRAM, a 40gb Western Digital hard drive,
> 3-1/2" floppy, and CD-ROM drive.
>

 

[Andy]

Archived from groups: microsoft.public.windowsxp.hardware (More info?)

On Thu, 10 Mar 2005 16:57:42 -0600, "\" AA Smith\""
<SmithRMS@Comcast.net> wrote:

>I'm working to resolve a strange problem.
>
>The initial problem with this computer several weeks ago was a defective 250
>watt power supply. I replaced that and everything seemed ok. The users had
>no further trouble with the system until last week when the screen went
>blank while the user was online. From then on, the user could not get the
>computer to boot up.
>
>I'm not referring to a BSOD situation; that would actually represent an
>improvement over the computer's current situation. The computer simply won't
>boot even though the Power light and the red disk activity light turn on
>when we press the power button. That is, the computer does not issue the
>usual beep after we press the power button, and it displays absolutely
>nothing on the monitor. The red disk activity light remains on solid along
>with the green power light until I unplug the computer. It will not even
>power down when we press and hold the Power button for a looooong time; much
>longer than the few seconds it should take to power the computer down.
>
>I tried replacing the Pentium III 450 MHz processor with another one, but
>that made no difference whatsoever. I reseated all of the connectors as
>well as the two SDRAM sticks. That made no difference either. So, I
>finally REPLACED the MOTHERBOARD. However, the computer STILL refuses to
>boot up. It continues to do exactly the same thing that I've described
>above. And, I've ruled out the possibility of anything being caught between
>the motherboard and metal cabinet.
>
>Is it possible that a defective hard disk could actually keep a motherboard
>from performing its initial startup process?

The easiest to find out is to disconnect the hard drive. Then power up
the computer.

> If not, I'd very much
>appreciate your help in determining what's wrong with this system. I've
>built and repaired several dozen computers, but I haven't run into anything
>like this until now.
>
>This computer is an ATX clone with an ASUS P3B-F motherboard, with a Pentium
>III 450 MHz processor, 128mb SDRAM, a 40gb Western Digital hard drive,
>3-1/2" floppy, and CD-ROM drive.