Fluorescent lamps can interfere with TV remote controls.
My parents recently had an intermittent problem with their television's remote control. For several months the remote only worked sometimes. The TV is a Sony Trinitron. The remote control is a Magnavox universal remote. I changed the remote's batteries, cleaned the infrared sensor on the front of the TV, and tested the remote on a VCR and on another TV. The remote worked fine with other devices, but the Sony TV only responded to it infrequently. I deduced that the problem was with the TV -- a bad infrared sensor, a loose connection, or a failed internal circuit.
I researched remote control problems using Google. I read several technical sites that talked about using voltmeters, oscilloscopes, or other instruments to troubleshoot ir sensor problems. After going through several pages of search results I came to a bulletin board post from 1996 that said to turn off any fluorescent lights in the room because sometimes they interfere with remotes.
I turned off my mother's fluorescent reading lamp and the remote worked perfectly. The lamp is a Balanced Spectrum Floor Lamp that my father bought a few months ago. The lamp has two settings; high and low. The high setting interferes with the remote even when the lamp is turned away from the TV. Apparently the reflected light waves are enough to cause a problem. The low setting does not interfere with the remote. Interestingly, the lamp does not affect the same remote's control of the RCA Home Theatre VCR, which is beneath the TV on the same stand.
Since I had to read so many Internet pages about remote control problems before I found the 1996 tip about fluorescent lamps, I thought posting the information here might be helpful.