Need some advice about malfunctioning GT56UHD transducer

[Bruinjay]

Hi Gang- while idling out of the Marina, my Garmin MFD sounded an alarm about not being able to read depth with my GT56 transom mounted transducer, which is currently my default…

in contrast the thru hull Airmar HW175 produced the crisp images.

I ran the boat for about an hour with no GT56 improvement.

shut down the boat and rebooted still GT56 poor image quality…

MFD connection was perfectly tight.

The boat and rigging is two years new. Any ideas what might be going on?

 

[seasick]

Did you check the angle of the transducer to make sure it hasn't been bumper up and did you check the underside for growth? Don't check with a bare hand!

Do you have issues with side scan and down scan or just one of the two?

 

[Bruinjay]

Thanks Seasick. The transducer angle is parallel with the water, and is clear of marine growth….I’ll head down to the boat in a bit to check things out. TY!

 

[SkunkBoat]

Are the red lines on the screen just a photo problem? or are they actually there?

Since it is telling you that it cannot detect a transducer on the 8-pin connector, I would check that connection.
But I think a GT56 is a 12 pin...no?
I think your Garmin has a 12pin and an 8pin sonar port.

Is the Airmar running from the same built-in sonar or do you have a separate blackbox GSD to run that? There can be a setup conflict if you have two sonar sources and two MFDs and you turn one on in the wrong order.

Is the Airmar new? Have you used both at the same time before with no problems?
Did you try turning transmit off the airmar and running just the 56?


Reason I ask is that they both use the same frequency and I would expect interference.
The Airmar appears to have interference in the form of vertical streaks. At 3 mph in 40 ft you should have a clean screen.

 

[Sauza45]

I think garmin released a new update for this. check to see if you have the latest update.

 

[Hookup1]

Frequency of the two transducers don't overlap. Should be ok there.

Use Active Captain to update the plotter software. Probably won't help though.

Go into the Garmin settings for the sounders and look for the transducer diagnostics. Give that a try to see if it picks anything up. You can also turn the transducers off one at a time to see if it makes a differen

 

[Bruinjay]

Thanks everyone for your input here. I ended up downloading the newest version of the Garman software. I then went into sonar and figured out it is the GT 56 UHD that’s reading incorrectly. My airmar through hole, 1875HW is reading perfectly. Now I have to get in the water and experiment with different pitches on the transom mounted unit to get good readings.

 

[wspitler]

We need more information as to what is actually driving your transducers. Do you have a separate black box to drive your through hull transducer? What type MFD is driving your GT 56? Many MFD‘s such as the 1243XSV, will not drive two transducers simultaneously. If your MFD has only one transducer input, then there must be an adapter downstream to connect two transducers. Do you have a single MFD or dual MFDs? There could also be a networked sonar black box such as a GSD24 that provides data to the MFD via the Garmin network cables. That is simply a video connection, whereas the transducer connection on the back of the MFD is a sonar internal to your MFD. To further troubleshoot your issues requires more detailed information.

 

[Bruinjay]

Thanks WS…I’m new to all this so don’t have all the answers yet, but after some dock diving and transducer adjusting seems ok now.