I am having a problem with this unit pretty much losing its sensitivity. I am running 2 units, a lowrance x510c, and a hummingbird 797csi2. I noticed the other day the my lowrance was not picking up fish, over places there are ALWAYS fish. The bird I use just for side imaging, but just for the heck of it, I switched the bird over to sonar and wouldnt you know it, there were fish arches everywhere, like I thought there would be. I keep having to do a manual reset of the lowrance for it to pick its sensitivity back up. Anyone else have the problem before, and what may be causing this?