Which component should I replace on the logic board?

Hi to all, I have had three of intel mac with fault like this: powering up, fans and HDD speed up, white LED on a front will light up, no screen, no sound and it will not boot. I know it will be mother board, but which part of it and which components are faulty or under which IC are dry balls is my question. It look like they having common issue, as have seen many of them on a market with same symptoms.