Testing The Installation - Garmin Fishfinder 320C Owner's Manual And Reference Manual

Testing the Installation

While it is possible to perform some checks with the boat trailered, the boat should be in the water to
properly test the sonar portion of the installation.
Press the POWER/BACKLIGHT key (see pg. 8) and the Fishfi nder 320C should power on. If the unit
fails to power on, verify that the wiring adapter is seated properly in the back of the unit, the Red and Black
wires are connected to the correct polarity, and that the 2-Amp fuse is installed and not blown. If the unit is
connected to a power supply that exceeds 35v DC, a "Battery Voltage High" warning will be displayed and
the unit will turn off. If the unit does not detect a transducer, it will automatically enter Simulator Mode.
When the unit detects a transducer on initial power up, a "Please set up transducer" message will
appear. Press the ENTER key (see pg. 8) to select the transducer type. Highlight your transducer type with
the ARROW KEYPAD and press ENTER. Press QUIT to return to the Sonar display.
Since water is necessary to carry the sounder' s sonar signal, the transducer must be in the water to work
properly. It is not possible to get a depth/distance reading when out of the water. As the unit powers on, it
should immediately start showing the bottom. Verify that the unit is not in the simulator mode. If the unit
is in the simulator mode, make sure that the transducer is connected properly to the unit. When you place
your boat in the water CHECK FOR LEAKS around any screw holes that have been added below the water
line. DO NOT leave your boat in the water for an extended period of time without checking for leaks.
Begin testing the installation at a slow speed. If the sonar appears to be working properly, gradually
increase the boat' s speed while observing the sonar' s operation. If the sonar signal suddenly is lost or the
bottom return is severely degraded, note the speed at which this occurs. Return the boat to the speed the
signal was lost. Make moderate turns in both directions and see if the signal improves. If the signal strength
improves while turning, adjust the transducer so that it extends another 1/8" below the transom of the boat.
It may take several adjustments to eliminate the degradation. If the signal does not improve, it may be neces-
sary to move the transducer to a different location.
NOTE: When adjusting the depth of the transducer, make the adjustments in small incre-
ments. Placing the transducer too deep can adversely affect the boat's performance and put
the transducer at greater risk of striking underwater objects.
Installation
Testing the Installation
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