This sounds like it could be a logic board issue, but without further troubleshooting we don't have much to go off of. You can start by disconnecting any non-essential components from the logic board (battery, hard drive, trackpad, etc.)—then attempt to power on the logic board in different configurations to see if you can get any response. If the logic board doesn't power on even in a minimal configuration then you most likely have a damaged logic board. At that point you would need to investigate the circuitry on the logic board to discover the cause of the issue. Good luck!