Guys I have this "Humminbird LCR 400 ID" fishfinder and I know its about 50 years but got it from a friend.I put it on the battery last week but nothing,I the took it to a electronics workshop but they say it got water in at some stage.I've got a small boat and was wondering if its possible to fix or should I use it as a sinker,I dont want to buy a R3000 fishfinder for my R6000 boat.Thanks for any advise.:kaykak