I purchased a B and G Zeus 2 chart plotter 9 months ago and had it installed in my Catalina 320. The dealer had some difficulty integrating it with my other raymarine instruments, the biggest problem was reading depth. After a few tries it worked. Yesterday when I fired up the unit to go for a sail, depth no longer was passed on to the Zeus unit and the charts reverted to the base charts apparently stored in the unit's memory. I had purchased and installed Navionics gold charts and they disappeared with out a trace. Anyone have any thoughts as to how to proceed?