108
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 Cause
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.
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.
107
Troubleshooting
Before contacting the Humminbird® Customer Resource Center, please read the
following section. Taking the time to review these troubleshooting guidelines may allow
you to solve a performance problem yourself, and therefore avoid sending your unit
back for repair.
700 Series™ Doesn’t Power Up
If your 700 Series™ Fishing System doesn’t power up, use the Installation Guide that also
comes with it for specific confirmation details, making sure that:
• The power cable is properly connected to the 700 Series™ Fishing System
control head.
• The power cable is wired correctly, with red to positive battery terminal and
black to negative terminal or ground.
• The fuse is operational.
• The battery voltage of the power connector is at least 10 Volts.
Correct any known problems, including removing corrosion from the battery terminals
or wiring, or actually replacing the battery if necessary.
700 Series™ Defaults to Simulator with a Transducer Attached
A connected and functioning transducer will cause the newly-started 700 Series™
Fishing System to go into Normal operating mode automatically. If, when you power up
the 700 Series™ Fishing System, it goes into Simulator mode automatically, even though
a transducer is already connected, this means that the control head is not detecting the
transducer. Perform the following troubleshooting tasks:
• Using the Installation Guide that also comes with your 700 Series™ Fishing
System, check to make sure that the transducer cable is securely connected to
the 700 Series™ Fishing System. Reconnect if necessary, and power up the 700
Series™ Fishing System again to see if this fixes the problem.
• Replace the non-functioning transducer with a known good transducer if
available and power up the control head again.
• Check the transducer cable. Replace the transducer if the cable is damaged
or corroded.
