Robertson Dataline depth issue....HELP

[northshoreone]

The old depth system had been acting up for a bit..you could turn it off at the breaker and wait for just a few sec. ...turn it back on and it would be ok for the day or several days. Now its showing random depths no matter what. I had the local tech out and he threw a new transducer over the side and hooked it to the black box. It did the same thing.. I found a black box Robertson 12v the same as I had on ebay from a upgraded system that was said to have worked. Received it yesterday and hooked it up. No go....does the same thing. What does the brain trust here have to say about this problem? The boat is sold and trying to check off a few issues prior to sea trial!! Time is running out!!
Thanks

[Pascal]

If neither a new xducer and cable or a new box help then how about voltage?

Or it could be some interference. Neighbor had similar issues on a 59 Marquis, Marine Max charged him hours or troubleshooting. It took me a few minute to see that they had run the xducer cable laying on top of an air handler motor. Any changes to the boat, any work done lately?

[SEVEN]

I had a similar issue with a radio and the tach. Each time I keyed the 🎤 the tach jumped to 3000. The motor didn’t but the tach did. I found the wires ran across one another. Once I isolated them the problem was solved. Hope your issue is remedied as easy as mine.

[northshoreone]

No, no work done lately in any area around anything connected or near the unit or wiring. The tech used a raymarine transducer to check the box...any issue with what he choose to check it with?
It has had on again off again issues like this for several years and killing the power and turning it back on always did the trick to bring it back in line.......no more.

[Boatsb]

Was the ducer even the right frequency?

The raymarine is probably a 50 /200 while the datamarune is probably 120 hrs.

Its old and probably not worth fixing. Especially if there's a newer one aboard.

[northshoreone]

I said I would try and fix it...but there is a newer one connected to the Garmin units that works just fine so it may turn into an Oh well.......cant be fixed....
I wonder if there are the correct transducer units available for that unit?

[Boatsb]

Plus you can only use one in a frequency at a time. Go with the better one.

[northshoreone]

The Robertson is not connected to the Garmin units only to the dataline displays. They are about eight ft apart in the bottom of the boat.