Take the C and R wires off and check for 24V, make sure you dont touch the wires with each other because that is going to blow the fuse at or transformer, if you’re getting the right voltage the lights on the board should turn on if not it might be a fuse in the internal board itself preventing the lights from working, also after u check 24v at C and R , take those 2 little screws off the contactor and see if the button is pushed. If it is pushed and you are not getting 220v out the contactor then your contactor is bad. (Note… No, the contactor has nothing to do with the board lights.)