Depth sounder woes...

[Lola45]

First you should know that my understanding of all this electronics networking is very rudimentary. It all started when my DSM30 started working only intermittently. I'm not really using the fish finder capability, I just want accurate depth readings. When I am running the engine the sounder reads accurately sometimes and reads nothing at all at other times. Strangely enough, when I'm sailing the reading bounces from not working at all to giving me readings of 25 to 30 feet when I'm in over 100 feet of water. Tech support has suggested, since I don't need the fish finder, to bypass the DSM30, cut the end off the transducer cable and connect the black, blue and shield wires in to the ITC 5. I would lose the fish finder capability but would still get my depth reading through my I70's. This sounded like a pretty simple solution but I still hired a tech to do this. The tech got me a transducer cable extension, connected it to the transducer cable and wired it in to the ITC5. I think we both expected it to pop up on the I70 but somehow the i70 wouldn't recognize the p319 transducer. He called tech support and they said "Gee, it should work." Each time we tried the I70 transducer search there was no recognition of the depth transducer. The weekend is here so we disconected what we had done and reconnected the DSM30 and the depth worked perfectly...for 20 minutes and then back to nothing. I want to be heading south in a couple of weeks but not without a working depth sounder. Any ideas?

[Chuck - Raymarine - Moderator]

Lola45,

The reported issue with the DSM may have been rooted in the transducer or within the DSM. For fault isolation purposes, it would have been recommended that the transducer have been tested to ensure that it was operational before mating it to the iTC-5. As indicated by the technician and as specified within the FAQ found here, it should indeed been possible to bypass the failing DSM and provide the system with depth data by interfacing the depth leads of the P319 transducer to the iTC-5. Calibration and offset would need to be applied via an i70/i70S MFID. When doing so, the DSM should be disconnected from the system.

When using an iTC-5, an i70/i70S Transducers Set-up feature will not list a depth transducer unless each of the following criteria have been met:
- the vessel must be located in the water and the depth below the transducer must be greater than 3' beneath the transducer ... this cannot be achieved when the vessel is out to the water
- the iTC-5 has been interfaced to a compatible and operational depth transducer supporting 200kHz operation
- the iTC-5 has been selected from the list of transducers and Depth has been selected from the iTC-5 transducers:
----- should the iTC-5 not detect a bottom return from which it will determine a depth value, then the Depth option will be grayed out to denote that it cannot be selected.

Accordingly, should the vessel have been located in the water in a depth satisfying the requirement above and have been interfaced to the iTC-5 as specified within the FAQ, then Depth should have been able to have been selected from the list of iTC-5 transducers. If not, then it may indicate a problem with the transducer (recommend testing it) or with the iTC-5 (replace it).

[Lola45]

Chuck,

All of your stated criteria for the depth transducerhave been met with the caveat that the transducer is a multi frequency transducer. Would that foul things up?

[Chuck - Raymarine - Moderator]

Lola45,

As long as the transducer supports 200kHz operation (as would transducers designed for use with a DSM30), it should work for the stated purpose. As indicated within my prior response, should the iTC-5 not detect a bottom return from which it will determine a depth value, then the Depth option will be grayed out to denote that it cannot be selected. Given the prior report of a depth related problem with the transducer/DSM, it is also possible that there may be a problem with the transducer. Please click here to view a FAQ addressing how a depth transducer may be tested. Alternatively, the iTC-5 may be tested with a compatible instrument depth transducer which has been suspended over the side of the hull.