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PC Not Turning On


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#1 dbd night

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Posted 27 October 2008 - 03:23 PM

Ever since we had to turn off the mains electricity in the house, my computers not been turning on. When ever i turn it on at the plug though, theres a strange clicking sound inside the computer case, when i opened it up the green light inside saying that there was power was constantly flickering.

This is before i even pressed the power button, its flickering even when its connected to the mains.

Any suggestion? Im stumped.... :thumbsup:

Thanks

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#2 garmanma

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Posted 27 October 2008 - 06:08 PM

Even when the light is on doesn't rule out the power supply. Flickering even makes it more suspect
Testing a power supply:
---------------------------------------

Caution: There are electronics inside the case that are very susceptible to electrostatic discharges. To protect your computer, touch the metal of the case to discharge yourself of any electrostatic charges your body may have stored before touching any of the components inside. As a safety precaution you should unplug the computer to avoid electrical shock.
-----------------
The purpose of this procedure is to bypass the motherboard to test the PSU.

Caution:
This procedure will involve working with live 12VDC electrical potentials which if handled improperly may lead to electrical shock. Proper precautions should also be taken to prevent electrostatic discharges (ESDs) within the case of the computer. For safety purposes please follow the instructions step by step.

First, shutdown your computer. Then unplug the power cable going into your computer.

Once you have opened the case, touch the metal of the case to discharge any static electricity.

The connector of the PSU which connects to the motherboard is readily recognizable by the number of wires in the bundle. To disconnect it you will need to press on the plastic clip to disengage it and then pull the connector up and away from the motherboard. Please take notice of the location of the locking tab and the notch on the socket of the motherboard, this will only connect one way as it is keyed. This wire bundle will have a memory of the way it has been installed and will want to bend back that direction, you may have to play around with it to find a position that the connector will stay in the same position while you run the test.

Posted Image

From the top left to right the pins are 13-24, the bottom from left to right are 1-12.


Please notice that there are PSUs with 24 pin and 20 pin connectors, the location of the green wire in the 24 pin connector is #16, and the green wire in the 20 pin connector is #14. If you look at the connector with socket side facing you and the clip on the top the number one pin will be on the bottom left corner. This makes the pin out for the 24 pin connector from left to right 13-24 on top, and 1-12 on the bottom. The pin out for the 20 pin connector from left to right is 11-20 on top , and 1-10 on the bottom. If you look at the connectors you notice that these are sockets that fit over the pins on the motherboard where the PSU cable attaches, this is where you will place the jumper. For a jumper you will need a piece of solid wire about the size of a paper clip (20-22 awg), preferably a wire with insulation. It will need to be large enough to fit firmly into the socket so that it will not need to be held in place while testing. You are at risk of electrical shock if you are holding the jumper when you power up the PSU. Insert one end of the jumper into the socket of the Green wire, and insert the other end into the socket of any Black wire.

Once the jumper is in place plug the cord back in. If the PSU is working properly the case fans, optical drives, hdds, and LEDs should power up and remain on. I would suggest that you not leave this connected any longer than is necessary for safety purposes.

To reconnect the 20/4 pin connector unplug the power cord, remove the jumper, and reconnect the connector. Take a moment at this time to make sure that nothing has been dislodged inside the case.
---------------------------
At this point you can use a DC Voltage meter to read the different rail Voltages. You will want to insert the black probe into any of the Black (-) sockets, and insert the Red (+) probe in the five different colored sockets, one at a time. Below are the five different colors and their corresponding rail Voltages. The Voltages should be within about ten percent of the given values.

Yellow +12VDC

Blue -12VDC

Red +5VDC

White -5VDC

Orange +3.3VDC

Edited by garmanma, 27 October 2008 - 06:09 PM.

Mark
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why won't my laptop work?

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#3 dbd night

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Posted 04 November 2008 - 03:10 PM

Hey garmanma, thanks loads for your help, i found out it wasnt the power supply, its the motherboard. Ive sent it away for a refund.

My only fear now is i might have to re-install windows because of a completely new motherboard (different chipset and hardware config etc.) and i was wondering, would i be able to avoid this by chosing a mother board with the same chipset? (by the way, This is my old motherboard its a iP35 chipset.)

I was thinking of replacing it with This One. What do you think?

Thanks.

Edited by dbd night, 04 November 2008 - 03:13 PM.


#4 garmanma

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Posted 04 November 2008 - 04:56 PM

Re-registering the OS after a hardware change is pretty simple. A quick call to MS and tell them what and why and it should be taken care of with no hassles
Mark
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why won't my laptop work?

Having grandkids is God's way of giving you a 2nd chance because you were too busy working your butt off the 1st time around
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#5 dc3

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Posted 05 November 2008 - 01:53 AM

You are correct about you concerns about the different chipset being a problem. With the exact same chipset you might not have a problem, but I would backup all of you important files and applications that you don't have installation CDs for to removable media just to be safe.

Family and loved ones will always be a priority in my daily life.  You never know when one will leave you.

 

 

 

 


#6 dbd night

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Posted 05 November 2008 - 11:17 AM

Thanks guys, im gonna order a new mobo and hopefully get it through by some point this week. Ill let you know how it worked out.




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