Our dedicated depth
display will from time to time (a few times each hour) switch from displaying the correct depth
to .1 feet. After enough time at .1 feet to make you start to wonder it will switch back to the correct depth. It always reads .1 when it switches from the actual reading. It has occured in depths ranging from 1 to 50 feet. Bottom was recently cleaned by the diver so I don't think there is anything on the transducer which is mounted thru the hull
. The unit is ~ 4years old and has worked fine until the past month or so. Any ideas?