The Roland Jupiter 6 synthesizer, like most Rolands of the 80s, used low-power static RAM and a battery soldered the to the CPU board to preserve user-defined sounds while the power was off, which worked incredibly well — it was common for the original batteries to last decades.
Alas, not forever. This original battery was now reading 0V.
Battery replacement is widely understood — desolder the original from the board, solder in some other 3V non-rechargeable battery (perhaps in holder), and away you go.
Here’s my choice of replacement aesthetic. I definitely wanted to use a holder so I wasn’t desoldering and resoldering every 10-20 years; but many of the holder approaches are on fly wires and then either bang around inside the synth or have to get stickied to a nearby surface, neither of which appeals to me.
This CR2032 holder had both solder tabs protruding outside of the footprint for easy hand-soldering, fit the footprint of the generous solder pads, and came in black (brown? brack?) that I felt didn’t draw attention to itself inside the synth.
I may go back and add yet more solder to the pads to replicate the vintage giant blobs; but it’s already working and saving sounds with the synth off.