Flasher freaking out

I didn't get to use my flasher at all last year (for ice fishing) but I did manage to make it out today (before the next big thaw).  The good news is that I caught 2 delicious bass and about 8 respectable bluegill.  The bad news is that before I was ready to quit, my Humminbird flasher, apparently, was.  It began displaying odd images (if it turns on at all).  I am charging the battery now (though I thought it was fully charged before I left) and am hoping that is the problem (dead or dying battery) rather than something in the flashers "CPU."  I guess I could just wait and see (if the charge solves the problem) but if not, that leaves me with deciding whether it will be worth it to have it repaired (it's 5 years old) or I if I should just zuck it up and get a new one.