Barring obvious trauma (the Walkman was dropped or such), it sounds like a component just got old and passed on. You might be able to take apart the Walkman to see if there is an obviously-disconnected wire or such. But getting into the unit non-destructively might not even be possible. And your time probably could be better spent looking for a replacement. :-(

Thanks, Steve. That's kind of what I thought as the Walkman is kinda old. The FM is still fine but I'll get a new one as I need both. Just never realized things could just go out that quickly. I'm definitely not handy enough to take it apart. :0)