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Troubleshooting
Display Problems
There are several main conditions or sources of possible interference that may cause problems with the quality of the information
displayed on the control head. Look in the following table for some symptoms of display problems and possible solutions:
Problem
Possible Causes
The control head loses power at
high speeds.
If the power output of your boat’s engine is unregulated, the control head may be
protecting itself using its over-voltage protection feature. Make sure the input voltage
does not exceed 20 Volts.
When the boat moves at higher
speeds, the bottom disappears or
suddenly weakens, or the display
contains gaps.
The transducer position may need to be adjusted. A mix of air and water flowing around
the transducer (cavitation) may be interfering with the interpretation of sonar data. See
your Installation Guide for suggestions on adjusting the transducer position.
Electrical noise from the boat’s engine may be interfering with sonar reception. See
Finding the Cause of Noise
for more information.
There are no fish detected, even
when you know they are in the water
under the boat, or sonar readings
seem weak or faulty.
Sonar readings may be affected if the transducer is not positioned correctly (i.e.
mounted at an angle, not straight down), or there is some kind of mechanical
interference, either because it is mounted inside a hull that is too thick for proper
sonar transmission, the bond between the transducer and the hull is not airtight,
or because the transducer is dirty. Check with your Installation Guide for guidance on
re-positioning the transducer, and make sure the transducer is clean.
Low battery voltage may be affecting the power of signal transmission.
Electrical noise from the boat’s engine may be interfering with sonar reception. See
Finding the Cause of Noise
for more information.
Finding the Cause of Noise
Electrical noise usually affects the display with many black dots at high speeds, and high sensitivity readings. One or more of the
following sources can cause noise or interference:
Possible Source of Noise
Isolation
Other electronic devices
Turn off any nearby electronic devices to see if the problem goes away, then turn them
on one at a time to see if the noise re-appears.
The boat’s engine
To determine whether the boat’s engine is the source of the noise, increase the RPMs
while the boat is in neutral and stationary to see if the noise increases proportionately; if
noise appears when you rev the engine, the problem could be the spark plugs, alternator,
or tachometer wiring. Replace the spark plugs with resistor plugs, install an alternator
filter, or route the control head power and transducer cables away from the engine wiring.
Cavitation from the boat’s propeller
Turbulence created by the propeller can cause noise; make sure the transducer is
mounted at least 15” (38 cm) from the propeller, and that the water flows smoothly over
the face of the transducer at all times.
