Hello, my name is Dave. May I make a suggestion? Before you replace the board, make sure it is not one of the door switches staying closed. If the light stay on when you close the door they automatically go out after about 10 minutes. The door switches are up on top at each hinge.
I should have mentioned that the temperature display will also go out when a door switch does not operate so this should be your problem. Please let me know what you find at the door switches.
Not sure how all this works exactly but I figured out the door switch last night screw can loose and the lever popped up. You were correct though not that you needed me to tell you that. Another fella said it was the control board clearly that was not the case. I'm a plumber and get asked a lot of appliance questions (I am in no way qualified to answer) how can I direct people straight to "you" and not everyone this sight?
This link should work. If you are satisfied with my answer make sure you accept my answer and not the first expert. Thanks.
Appliance Tech Dave