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HELP!! Computer power cycles on and off nonstop!

Last response: in Components
April 27, 2012 10:05:05 PM

I am having an issue with my computer where when i turn it on, it will turn on for about 2 seconds, but will shut off right away. The fans turn on and the cd drive blinks and makes noise, but it just turns off after a couple of seconds. I tried disconnecting the cd drive as well. It then powers back up on its own and will proceed to do this cycle. I have check the following...
-new ram put in (Corsair vengeance 2 x 8gb)
-new graphics card put in (EVGA gtx 560 ti FPB)
-i tried a known good power supply still had the same issue (current power supply is a corsair HX750 and was recently installed)
-I tried another working hard drive of the same OS and brand of harddrive (Windows 7 and samsung SSD 830 Series)
-tried using a different power supply cord, and tried plugging directly into wall.
-resetting the CMOS (shorting the pins to clear) and bios (taking the battery out)
-Also tried using the on-board HDMI port to connect to my monitor.

The only thing left it could be is the processor and motherboard correct? Both are only a couple of months old. They were both purchased at the same time.

-gigabyte Z68AP-D3
-Intel i5 2500K

Please help me or give me some more ideas to troubleshoot. I really don't want to go through the ropes with the motherboard and processor companies. TIA
April 27, 2012 10:36:31 PM

Sounds like a power or overheating issue to me. Are you sure the HSF is seated on the CPU? Has it ever worked or is this occurring just recently?
April 28, 2012 9:04:05 PM

egilbe said:
Sounds like a power or overheating issue to me. Are you sure the HSF is seated on the CPU? Has it ever worked or is this occurring just recently?

Yea, i tried swapping a known good power supply to see if it would even boot up, but it still did the power surge.

The issue started happening after i shut the computer down one day. It wasn't in the middle of the computer doing something. I checked the HSF and it is securely fastened and on the processor. The processor never really got that hot. I have an aftermarket HSF setup on there now so it usually cooled fairely well. I do have the 2500K processor overclocked to 4.1Ghz. But it never seemed to have issues with that setting. Any other ideas of what it could be? Any help would be greatly appreciated.
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April 28, 2012 9:13:30 PM

there is a way to test for a dead cpu and your system isnt showing the symptoms of it. it is showing the symptom of a dying motherboard though...
you have tried everything else and your motherboard is the only thing left...
but there is 1 thing left to try. remove the hdd. boot the machine and if you get to bios then its the hdd. if it repeats the same cycling then you know for sure the motherboard is the issue.
April 28, 2012 9:23:38 PM

Ok. I just tried disconnecting the SSD and it still does the same thing. I tried putting another known good SSD in the computer with the same win 7 operating system, so it should have booted from that hard drive if that was the issue. I can't believe that the motherboard is bad. I just got it like 6 months ago!!
April 29, 2012 1:38:36 AM

means nothing. motherboards go bad just as easily as any other component. the good news is if its 6 months old its a free replacement.
my m8 z68 went bad last week he took it back and had less than a week on his shop warranty, he got it replaced with a free upgrade to the gen 3. so like i say its more than possible.
April 29, 2012 2:16:13 AM

o ok. good. So did you get a hold of gigabyte for the replacement, or the place you purchased it from?
November 22, 2013 7:22:22 AM

How to solve a "power cycling on and off" problem.

When confronting a "power cycling on and off" problem, If you know how that system works, it makes it easier to trouble-shoot. Never do work inside the computer if there is power connected to the power supply. The computer is alive unless you turn the power supply switch off or unplug the main power cord. The main board uses the 5 volt line to keep the computer ready to receive the on or off command. The main board turns the computer on by grounding out the green wire going to the 20/24 socket ATX power connection. If you turn the computer off, or the main board detects a catastrophically unsafe condition, the main board disconnects the ground from the green wire.

There are several things that can cause this "power cycling on and off" problem.
The jest of it all is, the main board is reacting to an error, or an unsafe condition. The three most common problems are; the main board sees No CPU fan, the main board thinks the CPU is at an overheated condition, or the main board is bad. If the CPU fan is bad, not plugged-in, or you are using a fan with only two wires, this meets the "no CPU fan" error condition. For the CPU fan connection, a fourth wire is not necessary, but a third wire is. A bad CPU, the CPU's 4/8 pin power connection is not plugged in, a poorly installed cooler, or a bad CPU temperature sensor, can all cause an "overheated CPU condition" error.

If the voltages that are coming from the power supply are incorrect, or being dragged down by a short, this can also cause this error; this is unlikely, but worth checking. The Graphics card, BIOS and memory are three other possible but unlikely suspects. At this stage, the quickest way to troubleshoot this problem is to first check and reseat the main board's two power connections and CPU fan connection. Now check to see if you still have the problem. If you do, reset the BIOS, and try it again. If you still have the problem, Let’s do a minimum systems check. Remove all memory, unnecessary connections, and cards from the main board. Leave the case connector ("on and reset" button, LEDs, 4 pin speaker) and CPU fan connection only. Plug the two main board power (ATX and CPU) connections in from a "known good" power supply. Now check to see if you still have the "power cycling on and off" problem. If the problem went away, one of the items you unplugged is bad. Check them by adding them one at a time. If you still have the problem during the minimum systems check, there is one last area to check; the CPU. I have also seen a poor connection between the CPU and its socket, cause this problem. If that connection is good, if you have an extra "known good" CPU you can install, do so and check to see if the problem persists. If that also failed to solve the problem, there is little to no doubt that you have a bad main board.

NOTE about checking the power supply: If you wish to check the power supply by its self (stand-alone), bend a paper clip into a U-shape. On the ATX connector, plug one end of the paper clip into the green wire's socket, and the other end into any black wire's socket (ground). To turn the power supply off, just remove the clip. In effect, you are turning the power supply on and off the same way the main board does. As the power supply turns on, its fan will start running. You can now check all of the voltages with a multi-meter (under "no-load" conditions). Every Black wire comes from the same place, GROUND. When working inside the case, always remove power, and then wait for the main board's power light to go off. If it doesn’t have a power light, wait 10 seconds before you proceed.

I know this is a late post, but I did not see a thorough answer to the man's question.
Not every main board acts or reacts the same way, There are no perfect universal trouble shooting guides. However, this is a good general well-balanced guide, and will work well on any ATX main board.