Working machine no image no chime

2015 MacBook Pro that was bought last year in excellent condition. Took fall damage on the left corner and broke the display, but I could power it on, made a time machine backup, and the insides operated just fine. I did a total transplant into a refurbished display and used upper case assembly. Now, it won’t turn on, no chime, no image, but the fan spins. I get a green light on the charger, battery is connected. I double checked my cables, but I’m at a total loss.

This is not my first repair, I’ve successfully replaced other MacBook elements (display, keyboard, battery). I feel like I may have given this board static shock, or perhaps I was too rough on one of the elements. I made sure to touch my metal chair often. I’d hate to have to spend another $200 for a board repair after I made it this far. ?

Is there something I’m missing?