ST60 depth

[Arcflash]

My depth sounder, a ST60 Tridata will only display readings when the depth is ~10 feet or deeper. It starts to work when the depth reaches 10 and deeper and ceases when the depth goes less that 10 feet. Any idea why this happening??? It worked fine the last several seasons and just started this since this years launch. I have had to replace the speed transducer this year, could both transducers have failed over the winter???