I own a Yamaha RX-V540 which has worked well for many years. Recently when I turned it on it didn't light up. There was simply no display at all but fortunately the receiver is working fine. Since everything is set up through a Harmony remote I can use it without any problems but if I want to change any settings or change my setup I'll run into problems since I'll be working blind. Any idea of what's causing this? I don't know much about the internals of a receiver. Is there some type of bulb that needs to be replaced or is something else causing this? Thanks in advance for your help.