I am trying to help my dad out with his new boat and accompanying electronics. We took it out last friday for the first time, it's got an HDS-5 and and a HDS-8 units. The sonar works great as does the GPS. However when we tried to use the downscan/sidescan the screen just simply read "No Source" and no scan images would show up. Any thoughts on what this means or more importantly how to fix it? I'm assuming it means that the "source" means either the transducer or mabey just a loose connection. Thanks for the help.