The manual mentions the intelligent sensor board. The same thing was advertised (scroll down here: http://www.chesscomputeruk.com/html/...sor_board.html ) but it was never released.

The left edge connector does not do anything on the MK V. The module slot next to the LCD works, maybe the intelligent sensor board was designed to plug into there.

The "dumb" sensory board from 1983 only works with MK VI. Even if I forcefully add it to MK V, the program will just lock up.