Repair attempt on a broken Bluetooth Mini Speaker

I tried and I failed to repair this speaker even thou I did everything right and the speaker kind of works.
May 17, 2024 — 3 mins read — Electronics

Repair attempt on a broken Bluetooth Mini Speaker

What initially seemed like an easy repair, turned out to be a never-ending spiral of fault finding, micro soldering, and general electronics troubleshooting. It's a good thing that I enjoy doing this so it was worthwhile even with a sort of failed result.

This speaker was given to me by a friend to check and upon visual inspection, I could see that one of the wires going to the speaker was broken off. Given that the complaint was that it did not work, I thought that this would be an easy fix.


To open up the speaker, I used a flathead screwdriver to gently pry the foam cover on the top and reveal two screws under it. Removing those screws opened up the case cover and revealed the PCB inside.

As soon as I opened the case, I noticed that the USB port was broken off so this was one more thing to repair, additional to the speaker wires.

With the case open, I removed the speaker wires from the PCB and opened up the device entirely.

Speaker wire replacement

Since the original speaker wires were quite short, I prepared some new ones and first soldered them to the speaker, after I removed it from the casing. The glue was already broken so this was easy to do.

The wires were then threaded through the hole in the case and I waited till I fixed the USB port to solder them back to the PCB.

USB port soldering

The USB port was entirely broken from the PCB where all the pads were ripped off. To fix it, I first cleaned off all the leftover pads from the port and I then started removing some of the solder mask on the leftover tracks and ground planes on the connector.

Once I had copper exposed, I then soldered small wires to the tracks and I soldered the connector to these wires. One of the pins was giving me trouble so I used a longer piece of wire to connect the pin directly to a less crowded place on the board.

Battery check

With the port soldered back to the board, I checked the battery and realized it was at 0V. Since this is a lithium battery, it should never go to 0V so I knew it was damaged. Because of the size, I did not have a replacement so I tried to revive it on my bench power supply.

This is a dangerous procedure so I don't really recommend it but it might be useful at times. However, it did not work at all and after a few minutes, the battery was back to 0v so it was gone for good.

Device test

To test the speaker, I used my bench power supply set at 3.8V so it mimics the battery. The device started with its blue light and I was able to connect to it with my phone.

After playing something on YouTube, I realized that there was no sound coming in from the speaker but everything else seemed to be working. The phone responded to the actions from the switch on the speaker but for some reason, there was no sound coming out of the amplifier IC.

Next Steps

After some poking around, I came to the conclusion that probably the amplifier IC is bad but I was not able to source it locally so I ordered some from AliExpress.

It will be at least a few weeks before they arrive so I will take a second look at it once they do. In the meantime, if you have any ideas on what to check, please leave them in the comments below.

Tools and materials

speaker bluetooth repair
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