Hi,
The A3102 I have had for over 2 years suddenly stopped working today. Was working, switched it off and when I came switch it back on nothing. Although when I connect it on USB to the computer it works, as soon as I unplug it it dies. Any thoughts?
It has been a wonderful speaker, good battery life, great sound, it would be a pity if it has died.
There may be a way to repair it.
If you’re willing to take some risk you may make it worse open it up and read off the cells used.
It may be lucky and a generic cell like 18650.
They knowledge is to know if they’ve wired in series or parallel is it saying 3.6V or other.
You’d probably lose any waterproofing unless it’s repackaged carefully with silicone.
Seems to be a battery problem.
If you are skilled I would try to open it and check the battery and replace it.
You can take off the front mesh to disassemble.
But be careful not to damage or bending it. 
Thanks,
I think it will be better just to buy a new speaker.
cheers
But you should try to repair.
If you got not the skills to do it, donate the speaker to somebody who got those.
Worst thing is throwing it into the garbage without an attempt to repair it.
Agree better to buy new speaker but if you never cracked open such a thing it’s an interesting thing to try, learn, you may fix it and be a spare, or at worst a learning experience. It’s probably two 18650 7.2V in that size, needed soldering.
Sometimes just opened and wiggle the wires fixes things if wire loose.
The next time it not be such a low cost replacement and the experience may then be useful. I’d at least try.
Cost of tools is for a new person more than the cost of the speaker, need soldering iron, solder, probably two cells , and silicone, a voltmeter to test cells and test solder, about $40 in parts alone. But once investment then you can repair expensive items later.