Touch screen is unresponsive

Did a battery replacement. In the process found the original battery had expanded and swollen, and warped the logic board.

Purchased a logic board on ebay, installed. Charged, see the apple screen, see the swipe bar to open, but the touch screen doesn't respond.

Double checked everything, and seems to be ok connection wise. I did have problems with the no 6 connection, but have no idea what that relates to. In attaching the no 6, it was difficult to seat, and don't know if the connection was good, or as secure as I'd like. May have to replace that tab completly. Also had a similar problem with no 7, which has the the same circular connector.

Does anyone know what no 6 and 7 relate to? Asked staff, they don't know.

Main question: what would cause the touch screen not to work? I have the original logic board, and carefully straightened the warped board back to flat, but would appreciate suggestions before I repeat the operation again.

TIA

Danny