Sony Remote problem

I have had 2 calls in 2 days for the following problem. One TV is a Sony Plasma and the other is a Sony 34" tube TV. Both are hooked up to a satellite dish. Both the Sony remote and the Satellite remote worked fine for awhile on the TV (power on, channel and volume up/down, etc.). Then they stopped working or only worked if you held the remote close to the TV. The batteries are new. The satellite remote continues to work the satellite box with out any problem. On the plasma TV, the problem only occurs when the TV is first turned on. After 30-60 seconds, they work fine. Has anyone run into this problem? Thank you.