After replacing just about everything on my CR-10S PRO except the motherboard, I went ahead and bit the bullet and purchased a new board. Due to COVID and stocking issues, I was just now able to install it.....and nothing. The fans come on, but the LCD screen is blank and Cura doesn't recognize that there is a printer attached. I'm pretty sure it was supposed to come with Creality stock firmware, is it possible that I have a bad replacement?
Since the same motherboard is used in different printers, your motherboard may not have any firmware installed. I would do a Google or YouTube search for instructions on loading firmware on your specific board.
Seems possible, you could try and load the stock firmware or tinymachines firmware on it. Did you try to connect to it via pronterface or an octopi? You may need to try different baud rates or auto in case the fw that is on the board has something else configured. Before messing with any of that stuff though, I'd suggest double(triple?) verifying the connections to the board just in case.
Also, what all did you swap before the motherboard?