The RM270 has a 5V USB output port (usually labeled "DC OUT" or "Charge"). Even if the manual doesn't emphasize it, you can charge your phone while playing music.
Solution: The internal battery is dead. The manual includes a replacement guide. steren rm270 manual pdf 70 portable
The Steren RM-270 is a popular entry-level universal remote control designed to operate up to two different audio and video devices, such as televisions (TV), DVD players, Blu-ray players, and satellite receivers. It is valued for its simplicity, ergonomic design, and low cost, serving as a reliable replacement for lost or broken original remotes. The RM270 has a 5V USB output port