I would suspect the interconnect. It may have been fine for a removal but not for a reconnection. Inspect it in the machine and see if any of the connectors broke reconnecting it. Also make sure it is well seated. A crushed or broken crimp can cause the machine not to boot.

are you getting any lights on the playfield? Have you checked the display fuse? Trying to determine of the board is booting but you just don't have displays.