Furuno Radar Trouble

doc · Posted: Fri Aug 10, 2007 2:59 am Post subject: Furuno Radar Trouble

I have a Furuno model 1623 Radar. It has worked flawlessly for over 200 hours. About a month ago we were cruising along in the dark and hit a tug boat wake a little hard and the screen went to dark, wide concentric bands with a dark center, very similar to a target. The next day, I pulled the radome lid. There is a little string that is attached to the radome that I though may have snagged the rotating antenna. Trashed the string, fired it up and the the radar worked fine. A week ago, I was cruising along slowly in light fog and hit a tour boat wake and the the screen did the same. The only thing I found in the radome later on was light condensation on the inside of the lid. A trouble code "No heading pulse" comes up on the screen. This is supposed to indicate antenna cable problems per the manual. System trouble shoot indicates ok. The antenna turns but will eventually make a catching sound and stop. The belt acts as if it is binding up a little but I can't imagine there is enough tension to stop the rotation. When I give it a little push, it starts up again and gives a fine picture. I talked to Furuno and they thought maybe the unit should be sent in for a newer, larger motor. It seems to me that the problem should be simple due to its acute onset but I can't seem to narrow it down. There was a point where it ran longer after I tightened the ground screw and I thought I had it licked. I went through all other connections and ended up getting a much stronger sounding motor but still get the binding up noise followed by eventual stop of the antenna. Any input would be appreciated. Thanks.

flagold · Posted: Fri Aug 10, 2007 7:38 am Post subject:

You've nailed the problem, it is the radome that needs to go back, not your monitor (although you can send that too for updates).

Sometimes the wire for the motor itself (in the radome) becomes loose. If it's under warranty you may not wish to play with it to much though.

doc · Posted: Fri Aug 10, 2007 11:14 am Post subject:

Thanks for the repy. I am trying to limit how much I mess with it but if I can fix something simple and get through the summer would be great. The more I think about it, it seems like the antenna is out of synch and that is what causes a binding and eventual catch making it just stop. It wouldn't surprize me if the belt slipped a few cogs causing it to be out of synch. If all else fails, I will box up the whole works and send it to Furuno.

thataway · Posted: Fri Aug 10, 2007 4:35 pm Post subject:

I suspect that the antenna (Magnatron) was stopped, by this "string"--probably from the cable bundle. Since it is belt driven, it may have stretched the belt--but I believe that there are also gears to reduce the speed. It is not uncommon for these plastic gears to be damaged when the antenna is suddenly stopped. It is more likely to happen with an open array, but occasionally in the dome, if something causes the antenna to stop suddenly.

I would send it back to Furuno and have it fixed properly.

doc · Posted: Fri Aug 10, 2007 11:33 pm Post subject:

Well, I think I found the fix and it was actually pretty simple. The belt streched just enough to cause the motor to bind and stop. I replaced the belt and so far she works fine and sounds normal again and will hopefully remain usable for our trip this weekend. Thanks for the input and suggestions. Bob, I inspected the plastic gears and they look ok.

thataway · Posted: Sat Aug 11, 2007 12:05 am Post subject:

Sounds good--stick with the new belt! Glad it was that simple! Just watch those wakes--and be sure that there are no "loose threads"--in the dome--a good reminder for all of us!

Captains Cat · Posted: Sat Aug 11, 2007 9:31 am Post subject:

I've got a "loose thread" too in my Raymarine dome. It is a safety line that keeps you from dropping the dome top overboard when you take it off. Maybe one end of yours came loose if it's the same in Furuno domes?
Glad you got it fixed. Where did you get the belt? I don't think our hardware store keeps them in stock.... Laughing

Charlie

doc · Posted: Sat Aug 11, 2007 1:43 pm Post subject:

We had a loose thread for sure. Tangled up in the antenna. We now have a thread in the garbage as I would have had to have a loose screw to leave it in. Got the belt from my friendly neighborhood Furuno repair man.