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System Went Down

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#1 copycat21


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Posted 22 June 2008 - 11:37 PM


My System went down please guys help me to solve the problem.

so here is the story ..

I dont know how but my system went down. To see what happend I opened the system and checked each and every component

I came to know that my NIC card was burned ( I Connect my NIC to ADSL router for internet )

I bought a New NIC Card and replaced it but still my system is not comming up

I checked my mother board for any burns but I did not found any (mother board LED is glowing ) I removed my RAM and checked, giving Beep sounds. Every thing looks fine but still my system is down

when I Switch on the system its doing POST successfully (as all components LEDs blink once0

but I see that my monitor LED is blinking (Green light),
when I take off the cable its shows no signal msg on screen but when I plug-in its again blinking (no display) (as if there was no signal comming)
My Keyboard is not getting power after POST
The HDD LED is glowing continiously (no matter how much time I keep the system on its glowing continiously)

I am stuck guys please suggest me.

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#2 dc3


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Posted 23 June 2008 - 12:59 AM

Hi Copycat21, and welcome to BleepingComputer.

This is a tough one, there all sorts of possibilities. Have you experienced any thunderstorms recently that could have sent a lighting surge through you computer? Any power surges?

If the network card was burnt that means that an unusual amount of voltage reached it, and if it could have reached this card it could have reached the motherboard and CPU as well. The LED on the hdd staying on is another bad sign, the LED should only be on when the hdd is retrieving information.

If you have a voltage meter you can try the following test.

The purpose of this procedure is to bypass the motherboard to test the PSU.

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.

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. Below are the five different wire colors and their corresponding rail voltages.

Yellow +12VDC
Blue -12VDC

Red +5VDC
White -5VDC

Orang +3.3VDC

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.

Edited by dc3, 23 June 2008 - 05:15 AM.

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#3 iceman88


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Posted 23 June 2008 - 01:39 AM

Yeah this work on my PC a while back just be careful. It's like a mechanical reboot.
Hope the problems is gone by now
Thanks guys for the nice info on the site.

EDIT: Commercial links removed

Edited by usasma, 23 June 2008 - 07:29 AM.
removed commercial links

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