While I would like to be able to take each and every one of you readers out and show you how to get the most from your sonar, I'm afraid I won't live that long. Hopefully what I can pass on to you in the next few paragraphs will help you knock a few bricks out of your own wall. These all work to locate fish and tell you what kind of depths you're dealing with, as well as what type of bottom your over and where your lure is positioned. The key is to trust your electronics. The first thing to do is make sure your batteries are good and charged.
Some sonars use standard D-cell batteries, some use small gel cells.
I have a Blue Box for my FL-8 that uses an enclosed lead acid battery that is of a deep cycle nature and can be charged fully after each use. I hate to think about going out on the ice and having the depthfinder quit after only an hour or two. It happens to my fishing buddies, it won't happen to me. The transducer I use is self-leveling. When I set it in the hole it balances out and stays perfectly level.