Raytheon R10 radar - suggestions please!

[tony_lavelle]

My trusty old R10 radar worked OK when I bought my boat early last year but I had to cut the scanner cable in the cabin when the mast was unstepped. After launching, 9 months later, I reconnected the cable by soldering each of the 12 cores of varying thickness, some shielded and at least one coaxial.

Now the radar warms up OK but after it says "Ready" and I press the Xmit button, the display goes bright and there is a stationary vertical line and a loud continuous beep, interrupted briefly every few seconds. It does not respond to any buttons except to turn it off. The ammeter shows a current draw of only 1 amp, which seems low.

I gather the most likely fault is corroded terminals in the scanner unit (radome). However before I shin up the mast with a screwdriver and WD40, can anyone suggest what else I can easily check? I do have the original manual but my electronic troubleshooting skills are very rudimentary.

Thanks
Tony

 

[greenalien]

The most likely problem has to be the thing you last changed, so re-check all your wiring - especially for cross-connections - some of the wiring colours are very similar - and short circuits. One of the coax cables is very fine and could easily be mistaken for a plain wire.
As far as the radome is concerned. these units have a known fault of developing fine cracks in the base, around the mounting points. Eventually, these get large enough to let moisture in, at which point corrosion becomes a problem.
The other known weak point is the cable in general, after some time the outer sheath gets brittle if it's exposed to sunlight, and will then crack, allowing water to penetrate, often a long way - this is usually a problem between the the mast base and the deck fitting.

 

[tony_lavelle]

Raytheon R10 radar - is special plug available?

Thanks for detailed advice. I don't have a deck plug, only a gland, which is why I had to cut the cable. I did it near the display so I could fit a new plug, though in the end I have rejoined the wires by soldering them individually and wrapping with tape as I went. I have checked the connections as best I can but the only way to do this properly would be to completely re-do it.

Can one buy these plugs and do you need special tools to fit them?

 

[greenalien]

You'd have to ask Raytheon - I've only ever seen the cables supplied as complete assemblies; normal installation methods are either to fit a deck gland with a large enough hole to pass the plug through, so no need to ever cut the cable, or to cut the cable after it passes through the deck, and make up the connections in a waterproof junction box, using a choc blok connector. The disadvantage of the latter method is that any leakage, such as through a split cable sheath or a poor deck gland, usually results in the junction box accumulating salt water, and everything inside corrodes.

I suspect that you are right in thinking that special tools are needed to fit the plug - It may be that your only solution is to replace the entire cable - not, unfortunately, a cheap option.

 

[npf1]

I reconnected my R20XX radar earlier this year following replacing a mast - partially with a new cable and partially with the old. As mentioned above, some of the colours & thicknesses of the wires are very similar so double checking your connection would be a sensible place to start.

BTW: getting hold of a new cable might not be easy. I managed to find one at Greenham Regis.

 

[greenalien]

getting hold of a new cable might not be easy. I managed to find one at Greenham Regis.

Yes, I think their Lymington branch was where I last saw one. The modern trend of using ethernet to connect everything, including radar, made the old, multicore connectors obsolete overnight, and the cost of a complete new cable may well be more than the entire set is worth.

The other subtle problem with these cables, is that if the cable is split to allow mast removal, then each time it is rejoined, it's likely to get a little shorter, and I've seen cases where this wasn't allowed for when the cable was initially cut, and now there is just a short 6" stub left poking through the deck gland...

 

[Billjratt]

When joining the cable, you could use multiple multipin plugs, rather than chocolate block. I did it with various products from RS components, on all the cables from the mast (radar, wind, 2 x AE, lights)
I used Din for signal, coax for AE and rubber automotive types for power.
Lots of silicone sealant when assembling and grease when mating, then bagged and stuffed up an inverted winch pocket at the foot of the mast.
Don't know the number of cores in your particular radar cable but it should be easy enough to accomodate them all on three different plugs, the split cable can be protected with self-amalgamating tape for about 6 inches to allow physical manipulation.

 

[tony_lavelle]

reconnecting severed radar cable

Thanks for the excellent suggestion. I cut my cable near the display unit above the chart table (not near the mast) leaving a few inches on the plug. There are 12 cores but as you suggest I could group them into different types and use multiple connectors as appropriate. Fortunately there's plenty of slack in the cable.

 

[tony_lavelle]

Now works but with almost continuous beep

I dismantled my soldered connections and found the inner coax core was touching its shield - how embarrassing! I remade the connection with some rubber sleeve on the coax core. The radar now works, very impressively in fact, but after a couple of scans the unit emits an almost continuous beep. The control buttons don't respond until you get a very short break in the beep every ten seconds or so. The troubleshooting section of the manual doesn't cover this situation.

Any ideas what could be causing this beep?