DFF3D

[philo]

Hi. I’ve have a Dff3d installed with ss54 transducer in the keel- aluminum boat. The unit was working well until it wasn’t. Initially it lost one side of swath and now most of it. I’ve had the black box tested by furuno. I tested the transducer with multimeter for short between common and transducer channels and tested fine. The shielding of transducer cable is contacting the clamp (without conductive tape as lost it) and the unit is grounded to aluminum hull. I’ve tested with everything electrically off that is possible. Attached photo shows with gain turned to 100 in 3fa of water and not able to read the bottom, hence I can’t create pgb data. Any help greatly appreciated.

 

[philo]

*running on timezero

 

[Quitsa]

Is there any way you can get access to another transducer you could plug into the DFF-3D box and hang over the side on a pole to see if you an isolate the issue to the transducer itself? The fault you show certainly has the earmarks of an issue in the transducer or cabling.

I am not familiar with using TimeZero but I assume you tried doing a hard reset of all the DFF-3D settings?

 

[philo]

Is there any way you can get access to another transducer you could plug into the DFF-3D box and hang over the side on a pole to see if you an isolate the issue to the transducer itself? The fault you show certainly has the earmarks of an issue in the transducer or cabling.

I am not familiar with using TimeZero but I assume you tried doing a hard reset of all the DFF-3D settings? Tha

 

[philo]

Thanks for your reply. The black box was put on another boat and it ran faultlessly. I haven’t done a hard reset in the unit- will try.

 

[Quitsa]

Thanks for your reply. The black box was put on another boat and it ran faultlessly. I haven’t done a hard reset in the unit- will try.

I think you may well have answered your own question. Airmar has a portable transducer test device TDT1000 that most marine electronics technicians should have in their shops. I believe that originally they could not test the B54 DFF-3D type transducers. However, the software was revised and now they can be used. See this Furuno document: https://www.furunousa.com/-/media/s...54_transducer_testing_with_airmar_tdt1000.pdf

I think that should be your next step if the reset did not help.

 

[Magnetron]

Hi. I’ve have a Dff3d installed with ss54 transducer in the keel- aluminum boat. The unit was working well until it wasn’t. Initially it lost one side of swath and now most of it. I’ve had the black box tested by furuno. I tested the transducer with multimeter for short between common and transducer channels and tested fine. The shielding of transducer cable is contacting the clamp (without conductive tape as lost it) and the unit is grounded to aluminum hull. I’ve tested with everything electrically off that is possible. Attached photo shows with gain turned to 100 in 3fa of water and not able to read the bottom, hence I can’t create pgb data. Any help greatly appreciated.

There's a few things here that have me a little concerned. First, has the transducer been inspected for marine paint or marine growth? It's a real concern, if you don't know it needs to be looked at. Second, I'm not concerned so much about dissimilar metals or galvanic corrosion; however has the installation been properly isolated (electrically) from the aluminum with zinc anodes? Have the zinc anodes been inspected recently? They are a sacrificial wear item. Alternatively, the hull of an aluminum hull is not the preferred ground point for this product. It is much more preferable to ground to a proper through-hull dyno-plate; for an experiment try using a wire with an alligator clip to the ground point of the DFF3D processor and toss the other end into the water, does it affect the returns? If so, remove the aluminum hull ground. It is possible that electricity or noise is traveling across the hull if you have one or more devices grounded this way.

- Maggy

 

[philo]

I can’t access another transducer or tester at this stage. The transducer face was dived on and was clean and all anodes in good order. The strange thing is the milt-section display of the three swaths performs faultlessly whilst the pgb mapping and section view is useless. The attached images with gain at 100 in about 25 fa, jiggly ride into sea.

I’m yet to drop a wire over the side, try tomorrow. Thanks again.

 

[philo]

I’ve dropped ground wire into the water - no change. Also ran the unit off battery power separate from the boat with everything on vessel isolated with no change. The thing that confuses me is that the multi section soundings are good but section/pgb aren’t.

 

[Deep Blue]

Philo,

What you are seeing is noise. (Especially with the Triple Beam) The most common cause for this type of noise is that shield on the transducer cable is not properly grounded properly under the metal cable clamp and the conductive tape and making a good ground to the DFF3D module.

Multi-beam systems (WASSP & DFF3D) are very susceptible to external noise and proper grounding is the key for good performance. Any lack of good grounding here will cause significant noise when the system is operating within deeper water when signals are weaker and you have to crank up the gain to get a good picture.

Also try to power off all the other electronics on the vessel and see if that clears up any of this noise. You can try to set the Interference Rejection to HIGH, and maybe slow the unit’s TX Rate

- Deep Blue

 

[philo]

I purchased a new transducer. Dropped over the side and worked fine. Seems old one ran out of puff after 12 months for some reason. Thanks everyone for the help/input

 

[Johnny Electron]

Thanks for following up. It is always good to learn the final solution.

 

[Deep Blue]

Philo,
Thanks for the update.

- Deep Blue.