Sorry for reviving this thread, but I have a little more info on what could be the culprit.

I had the same issue with my D865PERL board. No post, CPU stuck in reset. Turns out the CPU was unsupported. But even after placing in an celeron 2.6gHz, there wasn't any POST code execution going on.

Then I got an great idea to apply pressure on the ADP3168 buck converter chip. I powered it on when applying pressure and.... it worked!
...for a while that is. Then high side MOSFET started burning up.

Now I have replaced all the MOSFET drivers and the bad MOSFETs, but still, no Vcore whatsoever and no POST codes (due to missing Vcore).

Maybe this info will give somebody an idea of what's wrong here...