Hi guys! I have a 36" smart job... Originally I had a switching issue due to dust and cobwebs. Fixed that with some electronics spray. Now it switches perfect,but now it does not recognize any feed. All I did was pull the back cover off and blow it out.
Back up a bit, so it can switch from input to input but there is no signal on any of them? You had signal before you opened it? I'd say there are more issue snow, nothing much we can do over the internet, you may need to have a repair tech look it over, or replace the system board.