This might be helpful for mp3 speaker users. It about the charging port. You may have had one that had stopped working because the charging port is bad. If this is true with you, then you may want to follow this post and see how you can have I fixed without calling a repairer.

First, be aware that some mp3 charging port are usually not strong and easily pull out. But you may be easy to fix it with a simple method.

Here it is. https://obruche.com/2020/02/11/bluetooth-speaker-charging-port-repair/