you blew the fuse on the main board. its soldered on, so you cant really replace it yourself.
easy fix. 3 day turn around (if you ship "next day").
Marantz will return ship however it arrived, fyi.
I've done this twice.
be sure not to reverse polarity on that external battery !!
most devices just wont power on. the Marantz has a fuse that cooks. Happened to me RIGHT after I got it back from Marantz after blowing the fuse fucking around at home w/a new battery setup. I get the deck back the day before RCMH in Sept. for Panic. while at the show....the fucking cable came apart in my bag as i'm getting it setup. I put the cable back together (backwards...in the dark) and blew the damn'd fuse again !!
I've since "Nick proofed" my battery and cable so that it can not be done incorrectly. I suggest the same to all owners.