The {platform} PCB can be detached from the keypad/display assembly.

Warning
The display is connected to the PCB via a flexible flat cable at the top of the unit. This connection is fragile and must be broken loose before any attempt to disassemble.

To disassemble, follow all the steps but the last one under Battery. From there:

Note
Any attempt to further disassemble, or modify, the components shown in the diagram will invalidate your warranty.