Fishfinder woes

[batty1of3]

I have a tournament 4300 but it was acting kind of funny last time i took it out like it was only half booting up showed some lines on the screen then after a few tries it came up next time i tried to take it out it woudl not power on at all the time it started acting up i took some pretty heavy waves over the bow so mebbe it got seawater inside
charged up my battery overnight bait tank works so there is power but still no power on the ff. What i wanted to check is there anywhere that might service those or i could take it to get checked ? its kind of old but i dont have alot of extra money lying around to get a new one :P

so i'll be fishing blind tomorrow in la jolla that should be an adventure

another question do any of you guys not use fish finders?