Garmin Livescope on a 93sv echomap plus mounted on a Xi5 with Cornfield Crappie Mount. Anyone else have problems with the unit being unreadable at times and having to turn the gain to auto. Screen gets real black and can't see anything really. Im thinking possibly has some interferance with rocks as it happens in around 5-15 fow near rock bottom or bluffs but I could be completely wrong in that assumption.