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?
1720 Radar Problems
- Thread starter ParfittW
- Start date
The symptom is a short in the scanner or cable. It also could be the display power supply wont hold a load but hopefully the dealer checked that. Checking continuity was a good idea, but did you also check that there is no short from any wire to any other wire?
Thanks for the suggestion. I am not sure if the dealer checked the power supply as they seemed to be satisfied when they saw the display unit start up normally. I will be on the boat in the following week and will check for any shorts in the cable from the display unit to the junction block. I was considering disconnecting all of the wires from the array side of the junction block and reconnecting one at a time to see if I could further define the problem but I am not sure if that approach could damage the unit.
You don't want to be disconnecting or reconnecting live wires. I would recommend disconnecting at the scanner and the display then check full continuity from the top down while also checking that no wire is shorted to any other wire in the harness. Shorts are normally in the cable or a bad Modulator board where the FETs can short out.
Thanks again for the advice. I will complete the checks of the cable from the display to the junction block on the next trip to the boat and will need to put off the other checks to the next trip. I should have mention that the radar is on a sailboat with the scanner mounted half way up the mast so it will be a 2 person job to due continuity checks on the cable from the junction block to the scanner.
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