This is the former process for replacement.
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Download the original PDF file from Roland US: Roland_Memory_Card_Battery_Replacement.pdf
Memory Card Battery Replacement Instructions
The Roland M-512, M-256 and M-128 memory cards each have an internal battery.
If you need to replace the internal battery, please use the following images as a guide.
(A replacement battery may be ordered from Roland, US - at 323-890-3700, ext. 5301.)
1) Locate the battery tray and use your thumbnail or the blade of a small flat-head screwdriver to gently loosen the battery tray.
2) Gently pull the battery tray completely out of the memory card.
4) Take care not to touch the new battery with your bare fingers as this can shorten battery life.