I bought a Sony RM-VLZ620 learning remote and I couldn't get it to learn. I did everything I could think of, and was just about to RMA it when I found a forum post explaining the problem. While the remote will operate normally (send commands) just fine using rechargable batteries, it will NOT learn with them. Switching the remote to alkaline batteries immediately solved the problem. I didn't believe it until I saw it with my own eyes.