Humminbird 425 SX Operation Manual page 31

ADVANCED FEATURES
TROUBLESHOOTING
If you are using a transducer switch to connect two transducers to the 425SX,
ensure the switch is in the correct position to connect a transducer that is in water.
(If a trolling motor transducer is selected and the trolling motor is out of water, no
sonar information appears.)
If none of the above solve the problem, inspect the transducer cable from end to
end for breaks, kinks, or cuts in the outer casing of the cable. If the transducer is
connected to the unit through a switch, temporarily connect it directly to the unit
and try again. If none of these items identifies an obvious problem, the transducer
itself may be the problem. Be sure to include the transducer if returning the unit
for repair.
4. When in very shallow water, I get gaps in the bottom reading
and inconsistent digital depth indication.
The 425SX will work reliably in water .6m (2') or deeper. The depth is measured
from the transducer, not necessarily from the surface.
5. The unit comes on before I press POWER, and won't turn off.
Check the transducer cable—if the outer jacket of the cable has been cut and the
cable is in contact with bare metal, you need to repair the cut with electrical tape.
If there is no problem with the cable, disconnect the transducer from the unit and
see if the problem is corrected, to confirm the source of the problem.
6. I get gaps in the reading at high speeds.
Your transducer needs adjusting. If the transducer is transom-mounted, there are
two adjustments available to you—height, and running angle. Make small
adjustments and run the boat at high speeds to determine the effect. It may take
several tries to optimize high speed operation. This can also be a result of air or
turbulence in the transducer location caused by rivets, ribs, etc.
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