LG G6 lcd with frame replace

Hello everyone,

I tired myself to replace LCD with frame in my LG G6 phone. I think I do everythink propetly but when i want to turn on this phone i got black screen , and i dont know why. I noticed 3 flashing (6sec eta flashing) led inside phone (on the back) when i tried to turn on phone and when it is plug in into the electricity. And all phone is hot (15 minutes after plug in electricity).

best regards