This project was born out of necessity. My Bluetooth speaker stopped working all on a sudden. I opened up the speaker, found the PCB and noticed that the 5V DC jack is broken and as a result, it’s not charging anymore.

I spent some time studying the PCB, tracing the PCB routes and realized that the DC jack was designed to get power from a continuous supply and it charges a 3.7V(1200 mAh) Li-Po battery. The battery is then connected to all the components on the printed circuit board. I decided to remove the battery, extend the power wires from the speaker and directly solder them to a 5V continuous DC supply. Although the speaker lost its portability due to this redesigned model of the power circuit, I was able to fix it without buying any additional component. Plus, my use of the speaker is almost always stationary.

Image: exposed PCB after opening the speaker 

Broken DC Jack

TESTING MY SOLUTION WITH A BREADBOARD PROTOTYPE. I ALSO FOUND OUT THE MINIMUM AND MAXIMUM VOLTAGE I CAN SUPPLY SAFELY.

REDESIGNED POWER CIRCUIT WITH A DIRECT 5V CONNECTION (MANUALLY SOLDERED)                             

FINAL WORKING VERSION OF THE SPEAKER