Raymarine RL70c Radar Repair

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…Hayden with the Radar…

Our 2002 Raymarine RL70c Radar system has been having issues and presenting an error message that says “Antenna NOT Rotating.”  I called Raymarine and they told me it needed a new drive belt. We ordered one and, when installing it in Miami, I broke the new belt. Errrrr.

So, we ordered another one and this time, in Hope Town, Bahamas, I decided to take the entire Radome down off the mast and work on installing the new belt on the deck. This job took about 3 hours total in the bosun chair and about 20 minutes on deck to install the new belt. Once installed, I lifted the (heavy!) Raydome back up to the spreaders and remounted the dome to the mast mount, all while hanging in the bosun chair. My arms were killing me and so were my legs and hands from using the ATN Top Climber to climb a rope halyard myself.

Hayden’s shadow from the mast looking down

Once installed, we fired up the radar as I watched from aloft to make sure the antenna rotated. Yes, it worked just fine! So, I finished the install and reinstalled the cover and sealant at the mast and finally came down. Well, the radar worked for perfectly for three days. NOW, it says…..”Antenna NOT Rotating.” WHAT? YUP, it is broken again. Now we are very frustrated because we do not like to run full speed ahead at night without radar. To us, it seems very dangerous. We are now planning our return trip to the USA via daytime hops when we really prefer to run 24/7 and to run overnight. It is just easier to do because we can run in shorter weather windows. When we return to the USA, we will take down the Radome and send it to Raymarine for a full rebuild, if they can service equipment this old. If not, it looks like it is time to install all new electronics, because digital radars are not compatible with our chartplotter. This gear has served us well and owes us nothing after all these years!

The radar drive motor and old, stretched, drive belt

The antenna removed, so belt can be installed from the bottom

The new belt installed

Rewired unit at the mast

The radar cover reinstalled

Fire it up, warm it up

IT WORKS….yahoo….but NOW it does not!

The drive belt number #32110 Raymarine Part Number

The definition of Cruising? Fixing (or NOT fixing) your boat in remote locations! So true!


Every day we try the radar, but the message still says ANTENNA NOT ROTATING. We learned that Raymarine no longer accepts these units for repair and refurbishing, like we had them do in 2006. So, we continue searching on-line for possible solutions.

Look at this error message…

I ran the diagnostics tests using instructions found at Raymarine’s website. (Note that running diagnostics was not suggested by the tech I originally spoke to.) All systems indicate “PASS” except one.

Notice that we have run this radar unit for 3,917 hours! WOW, it has been used for many days.

The Ship Heading Sensor says “FAIL” and that may be the issue. I will need to find out.

Here we are in beautiful Green Turtle Cay at the Leeward Yacht Club, waiting out this LO pressure storm arriving soon, After it passes, the ocean will be too rough to cross back to USA for a few days, so we will wait. There are many IPs here, including IP460 Cutter Loose, IP40 Tin Tean, IP40 Dream Catcher, IP380 Zippity Doo Dah, and IP38 Tatoo II. We will have fun, while doing some further trouble-shooting.

———————UPDATE ————-SOLUTION FOUND——————

I have determined the possible problem may be the optical sensor that is related to the ship’s heading and the rotation. I found the official part, it is called:

Raytheon/Raymarine Radome Heading Pulse Opto Sensor PCB (R104) M92650 M92652-s

It looks like this:

This part costs $30, and I ordered one to be shipped to Florida and I will install this when we get to the coast. This may finally fix our radar system!

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