Turn the G4 over.

Remove the two T8 Torx screws from the middle of the logic board.

Disconnect the four indicated connectors from the logic board, removing tape as necessary.

Carefully lift the logic board up and pull it away from you. The logic board may catch on the back panel ports liner. If this occurs, use a spudger or non-metal tool to free the logic board.

This step requires some force, but if the logic board will not come up, make sure you have removed all screws and connectors necessary.

Remove the logic board from the computer.