This speaker sounds great so it was a disappointment when it died. Bringing it back wasn't so straightforward. The internal battery pack is a shrinkwrapped pack of two lithium 18650s. The protection circuitry is on the board itself, so without a valid (narrow) range of voltage on that connector the board will not power up.
It didn't look very straight-forward to bypass the protection circuit. So I threw the disassembled thing in a storage box and let it sit for a couple of years. Wanting to get my workshop cleaned out I grabbed it today and set to work. I removed the battery from where it was stowed beneath the board, and clipped the leads:
I put the bench supply onto these two leads at 7.4 V and 1.5 A and the speaker came to life no problem. I searched in my parts bin for an adequate power supply. I had some 9 V wall warts but their current output was far too low. What to do? Well, I wanted to use it in the workshop, why not just power it from the bench supply?
There was just enough room in the case for the banana sockets. I just crimped on a couple of connectors to the cut leads from the battery. Before reassembling I disconnected the cable to the USB charging port (still shown connected here). It would be bad to try and charge whatever connects to these banana plugs (although I suppose I could use this as an external 18650 charger...
Looks pretty good, and still sounds great!
My bench is still a mess, but this freed up a storage box to help with the organization efforts. By hook or by crook, my workshop will by tidy by the height of summer this year!