This Roland D-10 was sitting in a local vintage shop going unused because all its patches seemed to be stuck in split mode. A quick check online produced this forum thread. The synth was purchased with hopes that a new backup battery would correct the memory problems. Here are the steps that were used to replace the decades-old backup battery. Please take care if you decide to use any of these notes. Unfortunately, I cannot take any responsibility for damages that may arise from use of this information. Most importantly, be sure to unplug any device before performing repairs.
A CR2032 coin battery was purchased as a replacement. The numbering on the package reads DL2032. This is exactly the same battery, just under the Duracell brand.
Begin by removing the all screws on the bottom of the keyboard, except the screws which hold the rubber feet. There should be 14 screws.
On the back of the keyboard, remove the bottom row of screws. There should be 6 screws.
The bottom cover slides forward and up to reveal the mainboard underneath.
The battery is located towards the back in a black snap-in holder.
It can be a little tricky to remove. Gently lift the black tab and use a small screwdriver to push the battery halfway out past the tab. Do not remove it fully yet. Using a small pair of needle nose pliers, grasp the battery and pull it out past the black tab. This will help you avoid coming in contact with any corrosive residue from a leaking battery.
Here is the battery that was removed from the keyboard. Looking at the negative terminal, some leakage has occurred due to age. Be sure to dispose of the battery properly and absolutely keep the battery out of reach of children.
Slide the replacement battery into place with the positive terminal facing up and ensure that the black tab has locked it into place. The D-10 should now be ready to save patches. The back cover was replaced and a patch was saved to test the memory retention.