MB-1 Error Messages

[kawai2g4b]

Ok, when I fire up my MB-1. Im getting the "C-1 to 256" "Err3" and "Err7" messages.  I looked up the manual to figure out the first two, but I can find any info on "Err 7".  In sum...do I just restore factory defaults for the C and Err 3 errors, if not, then what?  Also what do I do about Err 7 and does this mean that the battery needs replacement? 

[MarshallJMP]

That is in 95% of the cases a death battery,replace it and it should be fine.Keep us updated.

[kawai2g4b]

I'm relieved to hear that...that eases my suspicions.  I'm going to take it to the shop after Christmas after I sell one of my guitar amps, and then I will  keep you updated.