1986 WM-F107: The Solar Walkman
The WM-F107 used the Sports Walkman as a technology demo. It paired a sealed body with a large solar panel and an internal rechargeable battery, using sunlight to power the radio and recharge the pack. Solar did not run the tape transport directly, but the system worked as intended. Despite its size, it still carried auto-reverse, Dolby B, metal tape support, and an AM/FM radio, with much of the circuitry packed into the cassette door. Expensive and complex, it was never repeated.



