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Mother Board Failure


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#1 JUICYboy

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Posted 24 March 2010 - 07:51 PM

This is a:
Dell Desktop w/ Intel P 4, 512mb and Agp Graphics card.

Symptom:The Computer does not turn on or bring up anything on the screen.
I think the MotherBoard has gone bad and the reason I say that is because I have tried the following Techniques:

1)Turned on with button, Motherboard does not turn on.
2)I took out RAM stick there is NO Beeping code.
3) When I plug power to cpu it automatically spins the fans.
4)No control over power even if I try a screw in the power port to shut it off that way.

What do you guys think, any other tips before I conclude that it was the motherboard?

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#2 MrBruce1959

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Posted 24 March 2010 - 08:36 PM

What is the general condition of the capacitors on this board?

In case I lost you here, capacitors are those round canister looking things located around the motherboard. They are also used for filtering in power supplies.

These store a charge like a battery does and are also used as filters to remove the ripples out of the current's sine-wave.

Over time these can leak, which is noticeable by inspecting the silver top of the capacitors body, if you see a black looking goo on the tops of any of the large capacitors, this capacitor is failing.

Some people who have basic electronics knowledge have been known to re-cap a motherboard, restoring it back to general useable health.

Also check the motherboard for evidence of over-heated parts or burn marks.

I am not sure what you mean by 4)No control over power even if I try a screw in the power port to shut it off that way. What do you mean by a screw?

You may also have a problem with the +5 Volt rail of your PSU, a +5 volt voltage regulator may have gone bad in your PSU.

Using a multimeter and testing the red wires from the PSU should show at least a 5 volt reading on the multitester.

Make sure the ATX power port is plugged all the way into the motherboard's socket.

Make sure your power/reset/sleep switch on the tower's front panel is not faulty, as this to can cause issues with a motherboard not powering up correctly.

Trouble shooting can be frustrating task, but if you look for and try what I suggested above you might bring this board back to life.

Good luck and please let us know if this has helped you in any way.
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#3 JUICYboy

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Posted 24 March 2010 - 10:07 PM

What I meant about the turning it on with a screw driver in line 4.
You now how you can turn on the computer by touching the PWR pins together with a screwdriver, on the motherboard were the pwr switch goes to. :trumpet:

1)Capacitors are GOOD, they are clean no marks and they do not look like they popped.

2)ATX Power-supply is Good. I see the light on MotherBoard Come up. I also checked Motherboard with other ATX Power-supply. MotherBoard Does Not turn ON.

3) What I did from last post is: Cleaned all Components I checked the Volts On the C-mos battery and I replaced it because Volts were way below 2V.
I got the motherboard to finally beep, because it was missing RAM.

Here is a PUZZLE I can't figure out maybe you can. :thumbsup: :flowers:

1)Sometimes The Motherboard turns on computer with me connecting the ATX plug to the MotherBoard Port.
Sometimes it does not.

2)It will not turn on with switch or screwdriver.

This Leads me to believe that the switch is bad, but then how come it wont let me turn it on with a screwdriver in the PWR port on the MotherBoard.

Hmmm, I just can't figure those 2 things out, but I bet there a source of a problem.

I will keep this posted until I fixed it. Thank-you for your help

#4 MrBruce1959

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Posted 24 March 2010 - 11:15 PM

Ok I understand now what you mean by using a screwdriver to short the pins that normally go to the power-on switch on the tower.

If replacing the switch does not correct this problem, you may have a relay inside the PSU that has dirty contacts making an intermittent connection.

Please use extreme caution while servicing the power supplie's components as there can be potentual for a severe electric shock from those large electrolytic capacitors.
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#5 JUICYboy

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Posted 25 March 2010 - 03:04 PM

I found the Problem:

The culprit was the CPU after all. After buying a Power Unit it turned on w/ out a glich.

I fought it was the motherboard because I saw the power light on the motherboard turn on. The light that says it's getting power from Mother Board.

However the Power Unit was faulty and was not suppling the correct Voltages to power up the comp.

It was a challenging task but I liked it.

Well thanks for helping me out. I learned a lot. Most importantly I learned to think clearly and use common sense.

God-bless. :thumbsup:




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