DELL LATITUDE 7400 - NOT POWERING ON

I bought three "no power on" motherboards from my friends in a local shop, and this week I'm going to try to repair the first one, a Dell Latitude 7400 with motherboard LA-G441P Rev 1.0(A00) . It's been a frustrating time in the last few weeks and I need a big win. Please like and subscribe if you like what I do, and mail me on therepairshare@gmail.com if you have any comments or suggestions.