1. Disconnect the top of the IOB (x8, x3).
  2. Free the harnesses along the top edge of the board.
  3. Disconnect the IOB:
    [A] Upper left (x1)
    [B] Upper right (x1)
    [C] Lower left (x1)
    [D] Lower right (x1)
  4. Lower the IOB bracket (with PCB attached) until it stops.