I kinda doubt that inaccurate readings are an issue of the transducer being bad.
The way these things work is that the "brain" of the sounder generates an electrical
pulse which is passed on to the transducer. The transducer generates an audio pulse at (usually) either 50 or 200 KHz, and this audio pulse travels through the water
to the bottom. Some of the audio pulse is reflected back up to the transducer, which "hears" the sound and converts it back into an electrical
pulse, and this is sent back to the "brain". The brain then measures how long it took to make the round trip. Knowing the velocity of sound in water
, it can calculate the distance to the bottom, which it then kindly displays for you. It repeats this sequence frequently.
Nowhere in this process is it required to measure voltages, only time intervals, and in my experience transducers either work ok or not at all.
Bubbles, turbulence, thermoclines and other phenomena between the surface and the bottom can indeed cause false readings, but these are always LESS than the true depth
. In the case of readings greater than the true depth
, I'd tend to suspect a problem in the electronics
... perhaps a fault in the clock rate or something else that
induces a timing error. It can't hurt to clean up all the connections, but I wouldn't throw my back out doing it! The good news (I think) is that you shouldn't have to pull the transducer out to fix the problem... just the electronic box.
At any rate, good luck with it.