I'm professional fisherman in Australia had fcv-295 for some reason unit won't read bottom few nigths then won't power on anymore, checked & changed fuse could not solve problem, so i removed unit put back "old video sounder fcv-581" but don't know what pin connect transducer 50B-6G to fcv-581. In boat had other through hull transducer did not connect, don't know "what's brand" it has 4 wires "red-black-white-green + bare wire" Any help? thanks.