[Elecraft] KPA500 Question

[r miles]

Had mine 2 months & love it. Curious abt. one thing. Programed the 
barefoot/amp setting for all bands. My question is about the memory for 
that function. Not had power failure of the mains yet. Is the setting 
stored in a battery back- uped internal memory? I  found no mention  of 
an internal battery or access to one in my manual.Not a big deal  but 
curious.

K9IL