Computer turns on then off - I have searched for answers!

MisterCray · Feb 1, 2015

Hey guys,

I really wouldnt be writing this if i were not desperate. I have read through all of the posts in the forum and everyone seems to have different answers for this issue. As the title suggests, as soon as I turn my PSU on, the motherboard LEDs light up and when I press the power button, the power LED flashes for a second and then the whole system goes off.

It was working all fine and I was browsing through some websites and suddenly it goes off!!

I have read through all be suggested solutions including issues off motherboard being shorted by a stray screw, testing the PSU using the paperclip, removing all the components, And trying to power it on by just connecting the CPU power Connector and the motherboard power connectors.

I also went through the check list posted here: http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems
I have only skipped the step with the breadboard testing.

I'm sure it's not an issue with a dead PSU or a dead motherboard and right now I have removed all of the components from my case and laid out only the motherboard and PSU on a cardboard. I'm really frustrated at this point, and I really hope that someone could help me out with this. You're my last help guys.

Additional information 1: The PSU fan is not running when I turn it on. Does the whole computer have to be running for the PSU fan to work as well?

Additional information 2: The build is more than 2 years old. The only major change i've done recently is to install a new AIO CPU Cooler. Its been running fine since last week until now.

PSU: Corsair 850W Bronze
Mobo: Sabertooth Z77
CPU: i7-3770k
The new cooler: NZXT Kraken x61

Mattios · Feb 1, 2015

Is your CPU cooler plugged in to the CPU header? The system may not boot without it.

Also have you tried booting with some RAM?

Markkk · Feb 1, 2015

Firstly you have done some great testing

Just a question to help us direct you in the right direction

1) How old is this config, New build or 3+ months old?
2) All that shielding can you remove it for testing & inspection?

There are mainly 3 reasons why a Computer wont turn on;

1) Power
2) MB Fault
3) Bios

1) PSU Failure, Wrong Cables (note modular PSU require the cables that came with unit- N/A for you), Cable not plugged in
2) Faults, MB Component failure, Pwr Switch failure (power switches do break it is a momentary connect so you can use reset switch to test)
3) Bios, Reset bios either by pin short or battery removal

Other things that can work - Refit CPU

Your Corsair PSU fan will not spin until it has 200W of load this is a design feature

MisterCray · Feb 1, 2015

Thanks for the replies guys.

1. I have tried booting with cpu fan plugged in and without.
2. I have tried it with my memory sticks. One, two, and none (I have 2 sticks, 8 gigs each)
3. I'll try removing the shield. I'll update you on that soon.

I have updated the main post with additional information regarding my Build's age.

Its an absolute puzzle to me right now.. I'll update you guys soon.

Update: Ok! Shields out now. Dis the same tests again. But still nothing.

leigh76 · Feb 1, 2015

Markkk's list of stuff is defo sound advice.

Have you reset the BIOS?
Almost sounds like a failed overclock.

Markkk · Feb 1, 2015

Do you have a system speaker anywhere or onboard?

Does it beep when turned on

Hold on removing shield this board boast a 5 year warranty http://www.asus.com/Motherboards/SABERTOOTH_Z77/

MisterCray · Feb 1, 2015

I've tried the reset bro. Nothing.

I just hope after all this, the fix doesn't turn out to be some damned screw which i could've removed in the first place without ripping my build open. (Tongue)

I really dont think theres an issue with the mobo to use the warranty. Btw, no markk, i dont think theres an onboard speaker in this one. I have to depend upon the LEDs and the fans to know if the mobo is working.

leigh76 · Feb 1, 2015

I guess next step would be re-seat the cpu and cooler.
How close are the heatsink screws to mosfets etc? they aint touching are they?

PS: check inside case make sure a standoff hasnt snapped or vanished.

MisterCray · Feb 1, 2015

I guess, I'll try reseating the cooler. I dont have any thermal paste with me, so I cant reapply. Will have to use the same. Will update on that soon.

Btw, the pattern I failed to notice before. I switch on the power. LED flashes, cpu fan gets a nudge. Then everything goes off. 2 seconds later, it auto attempts to power on again and immediately goes off. Thats it.

Markkk · Feb 1, 2015

I don't see on board speaker either - Can help especially if it beeping weird beeps but if it shutting down instantly on power probably would not hear beeps

Your don't have a spare PSU? or Old MB to test the PSU by any chance

I have a MB that was supposed to be bullet proof - Became useless garbage due to failed power management chip.

Markkk · Feb 1, 2015

That post of your power pattern sounds more like Power management chip failure...
But Still do test the PSU if you can

I really hope Re-seating the CPU works (very very small chance)

MisterCray · Feb 1, 2015

Okay. I tried to reseat the CPU cooler and... Houston we absolutely have a problem!

In the picture, You can see a patch of Arctic Silver going down from the standoff to the components below. should've happened when I tried to install my previous cooler.
This should be a cause of concern right? If so, how would you advice me to clean off the stuff. A Q-tip? I've still got the thermal material removers that came with the Arctic Silver. Shall I proceed?

Markkk · Feb 1, 2015

Remove the actual CPU and put it back in is what i was referring to.

Spilled thermal paste - artic silver not to sure of compound ingredients and weather this can cause issues if spilled

Application of thermal compound is recommended "1 drop" in the center of the CPU or Heat sink, like you would imagine a water drop as the best way to apply - Other methods of X and smearing etc are just a waste of time.

Personally not sure on best method for clean up. (Compressed air wont work here)

MisterCray · Feb 1, 2015

Cleaned that stuff and reseated the cooler. Re-installed the cpu as well. Still not working....

leigh76 · Feb 1, 2015

There seems to be a lot of TIM down left hand side of cpu too.
Not saying this is the problem you have, but I would defo clean that up and get fresh paste.
Maybe get a tin of compressed air if poss and clean those dust bunnies too

and actually remove the CPU and reseat it too, check pins etc.
*EDIT* sorry I was too slow in replying

Markkk · Feb 1, 2015

After all isolation testing and checks final results to date are.

PC shuts down 2 seconds after turned on - Fans spin momentary

1) MB detected Fault shut down to prevent damage
2) MB Failure (possible power management system chip)
3) Faulty PSU - cannot provide power of incorrectly power so psu shutdowns due to PSU fault

One of these 3 is the last possible fault left

Test with Replacement PSU or Test PSU with PSU tester
Can of compressed air to clean MB (hail mary)

leigh76 · Feb 1, 2015

Nice

Glad it seems to be sorted.
Have fun

MisterCray · Feb 1, 2015

Sad update: Problem not solved. Only became worse. Mentioned here: http://www.tomshardware.com/answers/id-2517695/system-boots-cmos-jumper.html

Computer turns on then off - I have searched for answers!

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