Hi all. Thanks for the help in advance. Recently purchased a boat outfitted with rdp-139 plotter, ert-6/10 sounder, and rsb-0071 radar. All of the sudden the rdp-139 will not power up. Pulled all of the network/data plugs and check the voltage at the end of the power cord. It has a constant 12.5-13 volts. I tried to power it up with nothing else plugged in and I’m not getting anything. Unit does not beeb and the screen does not turn on. What’s next?