Intermitent FF issue

[MikeWood]

I've got the Navman FF 4600 on my Amberjack. Unfortunately, the depth reading disappears and the scrolling of the screen stops for sometimes significant periods of time. I'm talking 30 seconds or even a minute or more, then all of sudden, it reappears and everything seems normal with the scrolling. Seems to happen more often in very shallow water, but not exclusively, so it might be coincidence. Any thoughts on what causes this? Transducer? cable? maybe a the plug is loose behind the unit (flush mounted in the helm)?

Thanks,
Mike