Dell R640 power stay orange - not blinking - the server doen't sart

Hello, 
since i replaced the both processor xeon gold 5152 by two xeon gold 6230, my server doesn't boot at all.

on top left, the electrical power stay orange, on top right the Power button led stay off, but i can hear fan start every 20 sec.
Please, is there any body can help me ?
Thanks for your reply
BR