Display Problems - Humminbird 500 series Operation Manual

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
The control head loses
power at high speeds.
When the boat moves at
higher speeds, the bottom
disappears or suddenly
weakens, or the display
contains gaps.
There are no fish detected,
even when you know they
are in the water under the
boat, or sonar readings
seem weak or faulty.
Possible Cause
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.
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.
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.
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