Simrad NSS 3 depth issue

[Misfitts]

Hello fellow boaters, I am looking for insight.

I have a Simrad NSS 3 installed on my Catalina 30. After purchase, we had to splash and move quickly, and I didn't get a chance to go over transducers. So, I'm sure you would all be surprised when I say I haven't had a reliable depth reading since owning the boat.

In short, a number shows up under depth other than 1.6/1.7 randomly under motor or sail. No real rhyme or reason to it. Otherwise, the reading constantly shows 1.7 ft.

Here's what I've done this far:

-ensured source transducers are selected
-changed depth max to 400ft
-updated to latest firmware
-reset to factory setting and setup
-cleaned transducers

So far, same result 1.7ft.

I'm a tech savvy person, but marine electronics are new to me. I believe there may be up to 4 transducers hocked up to my unit (it has side and down scan as well), so not sure if I'm missing something obvious there with depth.

Short of replacing the transducer to get a depth reading, does anyone have any thoughts on cause and fix? I fear I'm missing something very simplistic.

Thanks everyone

[JoeRobertJr]

Hi, Misfitts,
Given the symptoms and what you have tried already, I am suspicious of a connection issue between your transducer and display unit.

This sounds like a good opportunity to trace out your entire system and document it in a schematic. Then you will know for certain how many transducers you have and how they are connected. While tracing the wiring, you can make sure the connection are all good, and that none of the wires are getting pinched.

I am in the process of cleaning up my own nav system and learned a lot by preparing a schematic and reading the manuals for all the gear.

Best wishes on tracking down the cause!

[Mexican Hat]

I can't help you with the problem itself though an unchanging, erroneous reading suggests either the transducer is bad or there's a connection problem.

On my Simrad transducer the wire is potted in the unit and is not serviceable. There is only the connection from there to the MFD.

The good news: the simrad gives you all the options (up, down, strange, charm etc.) from one transducer so the problem will most likely be somewhere on a single wire.

If there's damage to the wire itself they can't be repaired as they have multiple, shielded twisted pair internals. OK, you could do it, but it's really fiddly and hard and probably not worth trying.

And with the new transducers you can get Forward scan as well. If you've updated the software recently you may have got a notice saying "Forward scan is now enabled". Practical sailor did a review recently.