hi. i have a furuno vx2 rd-149 with a 1834c radar connected. i just replaces the plotter unit due to my screen going bad ( had a spare unit) and im having trouble getting my radar to work. the radar transmits. i can see it spinning on the screen and can hear it turning in the unit. no error codes. problem is, i cant see any targets. all get is fuzz/noise. any ideas?