Computer Chess Set - for spares or Repair (Loddon NR14)

This hand-held chess set (ComputaChess) is an early version of a computer chess game, being originally sold in 1981. It is in the original box, but the box is in poor condition and there are no instructions. While the set does power-up and seems to start a game OK, after a few moves, it fails (seemingly due to some sensors and lights not working).