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.