dish remote not working with sony lcd

I had the exact same problem and solved it by going into the sony menu for general setup. there is a option for a light sensor which comes "on" as a default. the light sensor optimizes brightness according to the ambient light which is why every now and then the remote worked (like when the dish installer was there). As soon as I turned off that feature, the picture became much brighter and the remote problem completely went away. hope that helps

in my case - sony kdl40vl160 with dish vip722 dvr