Hi,I recently aquire a Furuno RDP-139 display to use it with a classic navionics chart that I have. When I perform the self test of the unit all looks ok but it does not recognize the navionics chart, the program no. is 1950002023. I don't have any antennas (radar,gps) so I tried on simulation mode and live mode on the plotter but no luck. Any hints on what could it be. Thank you.