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Desktop Dead, Power Supply Failure?


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#1 afl0ck0fg0ats

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Posted 12 April 2014 - 03:38 PM

I was using my desktop computer for some standard gaming/Netflix and it just died on me; completely shut off. Everything else I had plugged into the power strip was still on so it wasn't a power outage in my apartment or anything. 

 

Pushing the power button does not turn it back on; occasionally I have noticed that when I press it the buttons on the front will flash for a second and one of the fans inside will rotate for 1 rotation or so. I've gone inside the case and cleaned, dusted, unplugged, and plugged back in most things but there isn't anything I can do with the power supply because I don't feel safe trying to take that apart. I only assume the problem I'm having is from the power supply unless there are any other ideas.  

 

Some small things I have noticed; there was a small flashing yellow light initially either close to the power supply or within the power supply itself; it had gone away by the time I got the case off and was inside. There was also a lit green LED directly on the motherboard. These details aren't much to go on but it does seem there is some ability for power to flow through it, just not turn on the system again.

 

Is there anything I can do to determine more specifically where the problem is without taking into computer repair services?

 

-Josh



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#2 JohnC_21

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Posted 12 April 2014 - 04:19 PM

If I had to hazard a guess, I would say it is the PSU. If you have a multimeter, you can check it as shown in the posted video.

 



#3 saw101

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Posted 12 April 2014 - 04:47 PM

Most computer shops will also test/check your PSU for free. They want your future business. Call first.

 

If you decide to go DIY, don't let all those wires & connectors intimidate you. Replacing a defective PSU is an easy job.

 

Don't purchase a factory replacement unit. Most often you can replace with a far superior unit for less $$.


I never make the same mistake twice....I always make it 5 or 6 times just to be sure!


#4 Bread&Butter

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Posted 13 April 2014 - 05:16 AM

First thing I would do is find a comparable power supply. Maybe you can borrow from a friend or rob Peter to pay Paul. Swapping your current power supply with a known good PSU is a quick process of elimination to determine whether it’s the PSU. Also, take a  look at the capacitors on your motherboard. If you see any of them bulging or leaking then it may be your motherboard. A quick Google search for "bulging capacitors" will show you what you're looking for.



#5 dc3

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Posted 13 April 2014 - 11:57 AM

There is a quick way to determine if the PSU is bad or if there is a problem with the motherboard.

 

 
 
The purpose of this procedure is to bypass the motherboard to test the PSU.
 
When a computer begins the boot process the motherboard initiates the start up of the PSU. Because of this it is difficult to determine whether the problem is with the motherboard or the PSU when a computer shows no signs of starting up. The purpose of the procedure is to determine if the problem is with the motherboard or the PSU.  For safety purposes please follow the instructions step by step.
 
Caution:  Since it will be necessary for your computer to be on during this procedure, you need to be aware that you will be working with live 12Volt DC potentials, which if handled improperly may lead to electrical shock.  The risks are minimal, but are there nevertheless.  If you are uncomfortable doing this procedure I would suggest  you not try this.  Anyone using this tutorial will be doing so at their own risk. 
 
There are electronic components 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 charge before touching any of the components inside.
 
This test is for ATX form factor PSUs. Some manufacturers use non-ATX form factor PSUs with 20/24 pin connectors that do not have the same pinout as a ATX form factor PSUs.
 
Notice:  Dell desktop computers with the Pentium ll and lll porcessors with 20 pin connectors, the Precision 410 and the Dimensions 8100 with the 24 pin connector all have non-ATX form factor pinouts.
 
First, shutdown your computer. Then unplug the power cable going into your computer.  To reduce the possibility of any shock press and hold the power button for thirty seconds to discharge any capacitors still holding a charge.
 
The connector of the PSU which connects to the motherboard is readily recognizable by the large 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.
 
th_main24index.jpg
 
From the top left to right the pins are 13-24, the bottom from left to right are 1-12.
 
Below are the pinouts for the 20 and 24 pin ATX form factor connectors.
 
atxpinout_zpsfe72bf61.png
  
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.
 
 
 
If you would like to have instructions that you can print out while you are checking the rail voltages see if the instructions below will help you.
 

 
 
The purpose of this procedure is to bypass the motherboard to test the PSU.
 
When a computer begins the boot process the motherboard initiates the start up of the PSU. Because of this it is difficult to determine whether the problem is with the motherboard or the PSU when a computer shows no signs of starting up. The purpose of the procedure is to determine if the problem is with the motherboard or the PSU.  For safety purposes please follow the instructions step by step.
 
Caution:  Since it will be necessary for your computer to be on during this procedure, you need to be aware that you will be working with live 12Volt DC potentials, which if handled improperly may lead to electrical shock.  The risks are minimal, but are there nevertheless.  If you are uncomfortable doing this procedure I would suggest  you not try this.  Anyone using this tutorial will be doing so at their own risk. 
 
There are electronic components 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 charge before touching any of the components inside.
 
This test is for ATX form factor PSUs. Some manufacturers use non-ATX form factor PSUs with 20/24 pin connectors that do not have the same pinout as a ATX form factor PSUs.
 
Notice:  Dell desktop computers with the Pentium ll and lll porcessors with 20 pin connectors, the Precision 410 and the Dimensions 8100 with the 24 pin connector all have non-ATX form factor pinouts.
 
First, shutdown your computer. Then unplug the power cable going into your computer.  To reduce the possibility of any shock press and hold the power button for thirty seconds to discharge any capacitors still holding a charge.
 
The connector of the PSU which connects to the motherboard is readily recognizable by the large 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.
 
th_main24index.jpg
 
From the top left to right the pins are 13-24, the bottom from left to right are 1-12.
 
Below are the pinouts for the 20 and 24 pin ATX form factor connectors.
 
atxpinout_zpsfe72bf61.png
  
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.

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

 

 

 

 





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