Navman Fish 4430 Installation And Operation Manual page 29

e) Ensure the back of the bottom surface
of the transducer is slightly lower than
the front and the front is as deep in the
water as possible in order to minimise the
generation of bubbles through cavitation.
(See the Transducer Installation Guide for
more information).
f) Check the transducer and power cable LT
connectors at the back of the display unit
are securely plugged in and the collar is
locked in place. The collar must be secure
for watertight connection.
g) Inspect the transducer and power cables
from end to end for damage such as cuts,
breaks or squashed sections.
h) Ensure there is not another fishfinder
or depth sounder turned on, which may
interfere with the FISH 4430/4431.
i) Electrical noise from the boat's engine
or an accessory may be interfering with
the transducer(s) and/or the NAVMAN
fishfinder. This may cause the fishfinder
to automatically decrease the gain unless
using Manual Gain. The fishfinder thus
eliminates weaker signals such as fish or
even the bottom from the display. This
may be checked by switching off other
instruments, accessories (e.g. bilge pump)
and the motor until the offending device is
located. To stop problems from electrical
noise, try:
- Rerouting the power and transducer
cable(s) away from the boat's other
electrical wiring.
- Routing the unit's power cable directly to
the battery instead of through a fuse block
or ignition switch.
4. Bottom is not displayed:
a) The fishfinder may have Manual Range
selected and the depth may be outside the
range value selected. Either change the
fishfinder to Auto Range or select another
depth range (see section 3-8).
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b) The depth may be outside the fishfinder's
range. While in Auto Range, the display
unit will flash the last depth displayed, then
display "--.-" to indicate that there is no
bottom detected. A display of the bottom
should reappear when it is shallower than
180 m (600 ft).
5. The bottom is displayed too far up the
screen:
The fishfinder may have Manual Range
selected and the selected Range value is
too high for the depth. Either change the
fishfinder to Auto Range or select another
depth range (see section 3-8).
6. Bottom echo disappears or erratic digital
reading while the boat is moving:
a) Ensure the back of the bottom surface
of the transducer is slightly lower than
the front and the front is as deep in the
water as possible in order to minimise the
generation of bubbles through cavitation.
See the Transducer Installation Guide for
more information.
b) The transducer may be in turbulent water.
Air bubbles in the water disrupt the echoes
returned, interfering with the fishfinder's
ability to find the bottom or other targets.
This often happens when the boat is
reversed. The transducer must be mounted
in a smooth flow of water in order for the
fishfinder to work at all boat speeds.
c) Electrical noise from the boat's motor can
interfere with the fishfinder. Try some
suppression spark plugs.
7. If the fishfinder beeps when turned on
but nothing is displayed:
The fishfinder may be operating, but the
contrast settings may have been set too
high or low. Power off the fishfinder. Then
hold and press
to the default contrast setting.
8. The wrong language is displayed:
(See section 2).
Fish 4430/4431 Installation and Operation Manual
to reset the fishfinder