My Lowrance HDS 8 Gen 2 is showing the "no source" and after reading other sites, sounds like it could be the ethernet cable...are these cables specific to the Lowrance and can you buy these anywhere, or do you have to go thru Lowrance. Is there a way of troublshooting to know exact cause before buying new cable? Or does anyone have one of these cables laying around that you want to sell in the Whitehouse , Tyler area?