Topic: New 798CSI Sonar didn't work first trip out

[skeeter92]

  Just bought a new 798CSI for a trip I have been planning for months. I took extra time to ensure to read the instructions and best practices, FAQ's, etc to be sure I got it right the first time. The weekend I had been waiting for came and I got in the water and the GPS & side imaging was working fine but the sonar did work. It continually read .6 ft. So at the end of the first day I double checked everything, finally called the tech support and they told me to disable the thru hull transducer (for running on plane) and only use the one that came with the unit so I spent an hour re-wiring and it started working. Called the tech support again and they said it is likely the Y-cable is bad. How can I be sure it's the Y-cable or the thru hull transducer, that transducer will not attach directly to the unit to test? thoughts please.

[Humminbird_Greg]

skeeter92,
Is it a true Thru-Hull transducer (mounts from the bottom of the boat through a hole in the hull) or an inside-the-hull transducer (gets epoxied inside-the-hull and shoots the signal through the hull) that you have?  I am assuming that it is the epoxied in inside-the-hull type.

The inside-the-hull DualBeam transducer will plug directly into the unit (if the cable will reach) and this is what you should do to test and see if it is the AS-Si-DB-Y cable or the transducer that is bad.

Now when you mounted that inside-the-hull transducer; did you in fact test the mounting location while on the water?  The reason I ask this is that the 0.6 foot water depth reading is indicative of a transducer that is not acoustically connected to the water.  This could be due to a failure within the transducer, a failure of the epoxy or air bubble in the epoxy, or even being installed in a location that will not let the sonar shoot through the hull.

[FuzzyGrub]

While you could ohm-out the Y cable, Greg's suggestion is faster and easier.   My immediate guess was the same as his with the shoot thru hull.   While the issue could be an air bubble / gap in the epoxy or mounting, it also could be a foam or hollow core hull, which will not allow this type of mounting to work.   

[Humminbird_Greg]

FuzzyGrub is right.  Some boats have stringers or other types of hull reinforcement or even air bubbles in the layers of fiberglass.  This is why you really should test the location prior to mixing any epoxy.  Take it from the expert here: a friend at Humminbird and I installed two transducers inside the hull of his boat before we read the directions and tested the location first! 

[skeeter92]

To answer the questions about trying the transducer prior to mounting; I was unable to do that, with the extensive drought our local lake is down so far that all ramps are closed so I was unable to get it in the water. I did mount it as close to the factory in dash flasher transducer thinking that area would be as solid as possible. I will try as recommended and try to connect directly to the head  and see if it's the Y cable. if it doesnt' work can the transducer be removed from the epoxy and re-installed in another location.?

[stillbear]

Yes you can move it to anothetr location.Take a board and a short handled sledge and rap it one time.