When I bought the boat it was equipped with a 1720 radar which was working fine. Last season it quit while operating. I found a blown fuse a replaced it but that did not solve the problem. I removed the display unit and took it to a dealer to check out. They put power on it and ip powered up normally. When installed back on the boat however there is no response from it. If i disconnect the plug that goes to the scanner and leave the power connected it starts up normally. I checked the pin for the plug from the display unit and it shows 12 volts. However when I plug the array back in and check for power at a junction block located at the base of the mast there is no power. I did a continuity check of the cable from the display unit to the junction block and the cable seems fine. Any ideas as to what the problem might be?