Is it just the display board you have replaced and not the main control board board?
Ok to be honest with you this is nearly always down to the display board that causes this fault were all the lights just stay lit.
But if you replaced that and it was the same then the main board itself will be the fault. As ive had it before were i replaced the display board and it was the same and it turned out to be the main board.
So 8 out of 10 its the display board but if after replacing the display board its the same then its the main board thats the fault on this.
Yes thats the main control board.