Hoover Nextra HNF 7168 3D washing machine?

I have 2 of the same washer and intended making 1 good one. I changed the main circuit board, but whan I turned the machine back on there were no numbers on the screen only 3 dashes --- in the centre screen. Could any one please advise me on what I might be able to do to rectify this prolem. Many thanks Mally