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PC turns on & off in boot loop. Tried everything I've found. Power supply issue?

  • Reboot Loop
  • Power Supplies
  • CPUs
  • Constant Reboot
  • Boot Failure
  • Systems
  • Motherboards
Last response: in Systems
March 19, 2014 1:36:32 PM

Hey everyone, I've extensively searched through the forum here and elsewhere but my PC is still failing to boot properly so I figured I'd start a new thread. Would extremely appreciate any input! :) 

Problem: After pressing power button, PC starts for about 1-2 seconds then turns off, turns on for 1-2 seconds again then turns off again and is stuck in that loop. Blue CPU cooler light and red mobo L.E.D counter flicker on for the 1-2 seconds then off.

- I have breadboarded and stripped everything down to essential parts; power supply, motherboard and CPU (with its cooler, not stock) with the two main power leads plugged into the mobo (24 and 8 pin), yet problem persists.
- Tried the paperclip short method with the power supply and it turns on and runs fine under no load.
- CPU has been remounted twice with thermal paste but no difference.
- There are no broken/exploded/bulging/damaged parts on the motherboard.
- Case fans and everything else is disconnected.
- I cannot acquire any spare parts from myself or others nor do I have much money to quickly spend on replacement parts without hesitation. Warranty has also expired on all parts besides RAM, which doesn't seem to be the problem though.
- I have checked for loose screws and wires and broken pins.
- I have cleared CMOS multiple times via taking out the battery for ages, moving the jumper as described on here and in motherboard manual and pressing the Clear CMOS switch on the back plate.
- I've let the PC rest without power for 12 hours.
- Held power button down for various lengths of time while PC is off.
- There are no beeps and have never heard any since first building it four years ago, so I guess there's no mobo speaker.
- Tried booting it while the mobo is not in the case, same problem.
- Cleaned everything, gotten rid of all dust and taken things apart, cleaned and put back together as if new.
- Tried using different wall power plug and different wall sockets.

Built this PC in 2010, never had any problems until last week. Watching YouTube while Folding@Home is running (medium priority) and the PC randomly shut off. Every time I tried turning it on it turned on and then off instantly, and I had to press power to turn it on again. Cleaned everything, tried many different methods online and one time when I powered on the PC something made a loud pop/explosion sound followed by a smell of smoke near the CPU area I think (happened fast). I cleaned more and reseated everything, problem was then solved somehow.

Couple minutes into playing intensive game next day it bluescreens. Underclocked GPU and increased fan speed very high (and loud) before gaming, no bluescreens occurred. Note that all parts inside are always low temps due to significant cooling.

Two days later I thought I'd overclock CPU in BIOS as PC was running slow IMO. Overclocked CPU ran perfectly fine, very low temps. Thought I'd then try one of the motherboard features which would supposedly increase PC performance by 40%, saved that setting, restarted PC and then from then on this whole boot loop thing happened and I haven't been able to even boot into BIOS let alone Windows since. I took a couple of photos of some BIOS settings before enabling the 40% system performance increase settings which I'll attach below.

Last thing I have done is open my PSU up to look inside, and noticed blue "gunk" around a screw, I'll attach a photo, though I'm pretty sure that's just glue or something irrelevant.

Last idea I've got is to purchase a power supply tester to make sure the PSU is working fine, which would mean the problem is with my motherboard or CPU, right?

Am hoping someone has another suggestion that doesn't involve spending money. If it can't be fixed, I'd at least like to identify the problem/faulty part and take it from there. Thanks very much for reading! Honestly any suggestions or information would mean a lot to me, thank you.

Motherboard: ASRock P55 Extreme
CPU: Intel Core i7-860 LGA1156 @ 2.80GHz
PSU: Antec 850W CP-850
GPU: ATI Radeon HD 5850 1G
RAM: G.Skill Ripjaws DDR3-1600 (4GB x2)
Case: Antec 1200

More about : turns boot loop found power supply issue

a b ) Power supply
a c 295 à CPUs
a c 173 V Motherboard
March 19, 2014 1:52:23 PM

when you clr_cmos did you unplug the power supply in addition to pulling the battery and using the jumper?

assuming the bios isn't the issue there are 5 things it could be.

1) you blew something on the motherboard
2) you blew the cpu
3) the ram died
4) the psu blew up
5) the gpu blew up

any one of those things could cause this problem. I would start with the ram. pull it out and try one stick at a time in each ram slot.

Then i would try another power supply (any power supply will do). make sure you have nothing connected you don't need

Then i would try another gpu (or try your current one in another computer)

Finally it's down to what you think went first. the Motherboard or CPU.
March 19, 2014 2:58:46 PM

Hi ingtar33, thanks for the reply. Yes I did all three and as stated in my first post, the problem happens without the RAM and GPU and I'm unable to acquire random parts or other computers. Any other suggestions?
Related resources
a b ) Power supply
a c 295 à CPUs
a c 173 V Motherboard
March 19, 2014 11:56:36 PM

unfortunately unless you can get your hands on another psu to try, or another cpu to try there really isn't any way to narrow it down without replacing parts in order of "likelyhood" for failure.

Personally i think your motherboard is the most likely part to have failed. that's just from decades of experience. That doesn't mean i'm right mind you. Call it a 4 out of 5 chance that it was the motherboard and not the cpu that died.
March 27, 2014 6:48:59 AM

Hello! i have had the same problem with my newly build gaming pc...i have a gigabyte mobo and the same problem..
First change ur psu if u suspect thats the problem ( i did too) then the problem continued for me and what i did was to check the supported memory for my mobo from the gigabyte site!
The ram i have at 1333 is supported but the same at 1600 it isnt! SO I underclocked to 1333 and everything is fine!
March 27, 2014 8:12:11 AM

It SOUNDS like a PSU. You can get one for $40-$50, and if it's not that you can always return it.

Also, if you have another computer you could attach the PSU to, if it doesn't boot with it in, then you know for sure that it's at least part of the problem. If the PSU went bad, it could have taken other things with it when it died.
January 30, 2016 11:46:47 PM

How long have you been running F@H? That's what was bootlooping me