Gigabyte GA-H55M-S2H power problem

[monaray]

Hi ..After extensive testing etc and swapping CPU and PSU I still cannot get my Gigabyte GA-H55M-S2H to go ..Heres what happens ...MB has one stick of Ram and i3 CPU .....I connect PSU and then power up by shorting the 2 power pins in the F socket..

The Heatsink fan goes for 30-36 seconds and then cuts out ...aprox 2-4 seconds later powers up for another 30-36 seconds and then cuts out again and keeps repeating this.....

Would be grateful if anybody has an idea what could be causing it...its not the PSU as have used several with the same result..its the MB ??? but why?
Thanks Mr

 

[UaVaj]

look like symptom of cpu 8 pin not connected.

if the 8 pin is properly connected. then cpu is dead/or socket pin is bent.

lastly bad memory will cause this type of boot cycle too. install in a different slot.

 

[monaray]

OK..I have pictures but I cannot post them but thanks for your comments..Mr