navman / airmar B60 problems

[ggendell]

I've got a Navman 4500 fishfinder with a airmar B60 transducer. It worked pretty good for awhile, and then suddenly became very weak. It BARELY reads bottom now, although I can hear it clicking as it pings inside the hull. The voltage is fine. Has anyone had any experince with problems like this, whether it be with a navman unit or a different one. I need to determine if the problem is in the unit or the transducer. On a different note, while trying to figure this out, I found another thru-hull transducer with a speed wheel. This one goes to my Faria gauges for the yamaha engines. It works fine, BUT IT IS PLASTIC, and cheap plastic at that. If It got hit hard I feel it could break pretty easy and I don't need a 2" hole in my boat, especially offshore. Anyone have any input on this, or know the replacement model??