No POST today

[Sam_107]

Hello!

I have a pc built some time ago that has been working fine up until recently. However it now won't POST.
When I power it up, all the fans spin up, lights come on, but after 1 second it all dies.

motherboard: Gigabyte z77x up4 th
CPU: i7 3770K
GPU: GTX titan
PSU: corsair HX850
RAM: 2x Patriot 8Gb 1866
Samsung 250Gb SSD

I have tried everything suggested in the "no POST" megathread
http://www.tomshardware.com/forum/261145-31-perform-steps-posting-post-boot-video-problems
- sadly to no avail.

Help would be genuinely appreciated!

Thanks for reading

 

[alexoiu]

Hi, If starting the board with only CPU and CPU fan installed, both 24 and 8 pin power cables connected, all other components/cables removed, does the CPU fan spin without stopping?

 

[Sam_107]

Hi, If starting the board with only CPU and CPU fan installed, both 24 and 8 pin power cables connected, all other components/cables removed, does the CPU fan spin without stopping?

Same behaviour - CPU fan spins up for around a second before switching back off.
I should add after about three or four seconds, it repeats; fans spin again for around a second before powering back off.

Thanks

 

[alexoiu]

Can you test different power supply?

 

[Sam_107]

Hi, If starting the board with only CPU and CPU fan installed, both 24 and 8 pin power cables connected, all other components/cables removed, does the CPU fan spin withoutmoo stopping?

Can you test different power supply?

I don't have one I can test - I've tried jumping the green wire with a black one and it's able to keep a fan powered.

 

[alexoiu]

Have you tried clearing the CMOS (unplug the power cord and remove the CMOS battery for a minute)?

 

[Sam_107]

Yeah, I've had the CMOS battery out for a couple hours, while I took it to the shop and got a replacement!

 

[alexoiu]

What components and cables are currently installed/connected on the board?

 

[Sam_107]

Ok. So I have the 24 pin power, 8 pin CPU power, and the cable that connects to the power button.
EDIT* and the cable that connects to the CPU fans, naturally 😉

Only component installed is CPU and heatsink. With fans. everything else is removed. My monitor is plugged via DVI at the on board port

 

[alexoiu]

Try removing the cable that connects the power button and starting teh board by shortly touching with a screwdriver the 2 pins on the board corresponding to the case power Button. See if the CPU fan still not spinning.

 

[Sam_107]

Ok - did that but still the same

CPU fans spin up for around a second. Then spin down and power is off for another four seconds. Rinse and repeat

 

[alexoiu]

If unplugging the 8 pin power cable, connecting a case fan to the motherboard and starting it, does the case fan spin?

 

[Sam_107]

With the 8 pin power unplugged, the case fans plugged in, when hitting the power then case fans flicker on for a fraction of a second.

 

[alexoiu]

Then either the board, or the power supply.

 

[Sam_107]

Ok, thanks so much for your assistance!

Is there any way to troubleshoot which is the fault? Perhaps with a voltmeter/ammeter? Or best to try and get hold of another PSU to test it?

 

[alexoiu]

If you can borrow a power supply, then you can test with it. Another option is RMA-ing them, if under warranty.
I'd test the power supply: https://www.youtube.com/watch?v=5FWXgQSokF4
If a connected fan does spin, then I'd RMA the board.

 

[Sam_107]

Thanks

Owe you a beer!

 

[alexoiu]

No problem. Please post back when finding a solution to it.

 

[Sam_107]

**update**

Took the CPU out and half the contacts were burned and black! Still not sure what caused it - don't want to risk it so replacing CPU, MOBO, and PSU to be on the safe side.

Thanks for all your help

 

[alexoiu]

You're welcome.
Thank you for the update.