Mobo mosfet is getting burnt

[meakcey]

Hi

I have MSI 970A-G43 mobo. 2 weeks ago when I tried to power-up the PC, fans were running but monitor was displaying nothing (some sort of signal was coming but just black screen). Then PC has gone to sleep mode and powered down. When I tried again, there was no clue about it would get powered-up. When I checked the mobo, I saw there is one of twenty mosfets has been burnt. Power supply only supplied the board if I disconnect the CPU side power. So I found the same mosfet and replaced the burnt one. Without graphic card and RAM, power supply powered the all the board again and I connected them too with a great hope. Powered again but same thing happened, black screen, after a while sleep status then powered down. I think, one of mosfet has burnt again but this time I could not see which one.
What could be the problem, graphic card or mobo? Graphic card is Asus R7 260x. I think I could find the possible problematic mosfet again. Also I have another same graphic card too. But I am suspicious about, should I connect or not the other graphic card to test mobo after I changed the mosfet? Which one causes the problem and is there a possible damage by affecting each other?

Thanks

 

[hang-the-9]

What is the brand and model of power supply? First thing I would replace is the motherboard since you already found an issue with it. If you think it may be the video card, test another one in your system and test yours in another system.