Motherboard turns on and after a fec seconds or minutes turns off, how do i fix it?

T0minator

Honorable
Apr 20, 2014
14
0
10,510
I brought my computer to a service, they tried many things (cleaning, checking the processor, PSU, RAM...) and concluded that my motherboard is broken. I bought a new MB, but now i want to try and check what could be wrong with my motherboard as a hobby, what could be physically broken with it.

Can you give me any pointers where to start? The service cleaned my MB up very good and i cant find anything wrong.