MFDBB battery on pcb

[Zephyros]

My MFDBB was made in 2014. The backup battery on the PCB is not the 'button' type, but a larger cylindrical battery connected by a wire and 2 pin connector.
I understand that this may be recharged during use by the system. Is it necessary to replace this battery routinely.

 

[Johnny Electron]

The battery you describe would be the type that is used on the newer "DUX" MFDBB. Talking to our repair center, they haven't saw one go bad. There is no preventive guidance on replacement. Because we have never seen one fail, we don't have them available in our USA stock. I would put that one on the not to worry about list as it comes to preventives.