I have a quite old unit with no manuals and my search on the net was
unsuccessful; any hint?

FURUNO
Radome: Model 1800, Type RSB-0016, Date 1988-12, Class X
CRT Display: Model 1800, Type RDP-043, Date 1988-12

Thank you in advance
Daniele Fua
"Luna Menguante" Swan 411-004