NorthStar EXPLORER 457, Installation And Operation Manual

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Northstar FISH 457/467 Installation and Operation Manual 58
B-3 Sonar fishfinding problems
3-1 The 457/467 operates erratically:
a Check that the transducer does not have
debris (e.g. weed, plastic bag) caught
around it.
b The transducer may have been damaged
during launching, running aground or
while underway with debris etc. If the
transducer has been impacted, it may have
been kicked up on the bracket. If it is not
physically damaged, reset the transducer
back to its original position. (See the
Transom
Transducer Installation Guide .)
c When the transducer is less that 2 ft (0.6 m)
from the bottom, the depth readings may
become inconsistent and erratic.
d Manual Gain may be set too low, which may
cause weak bottom echo or no fish signals. If in
Manual Gain, try increasing the Gain.
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 minimize the generation of
bubbles through cavitation. (See the
Transom
Transducers Installation Guide )
f Check the transducer and power cable
connectors at the back of the display unit
are securely plugged in and the collars are
locked in place. The collars must be secure for
watertight connection.
g Inspect the power cable from end to end for
damage such as cuts, breaks, squashed or
trapped sections.
h Ensure there is not another fishfinder or
depth sounder turned on, which may
interfere with this 457/467.
i Electrical noise from the boat’s engine or
an accessory may be interfering with the
transducer(s) and/or the 457/467. This may
cause the 457/467 to automatically decrease
the Gain unless using Manual Gain.
The 457/467 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:
- re-routing the power and transducer
cable(s) away from the boat’s other
electrical wiring.
- routing the display unit’s power cable
directly to the battery with an in-line fuse.
3-2 Bottom is not displayed:
a The 457/467 may have Manual Range
selected and the depth may be outside the
range value selected. Either change the
457/467 to Auto Range or select another
depth range (see section 3-5).
b The depth may be outside the 457/467’s range.
While in Auto Range, the display unit will
display “--.-” to indicate that there is no bottom
detected. A display of the bottom should
reappear when in shallower water.
3-3 The bottom is displayed too far up
the screen:
The 457/467 may have Manual Range
selected and the selected Range value is
too high for the depth. Either change the
457/467 to Auto Range or select another
depth range (see section 3-5)
3-4 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
Transom Transducers Installation Guide , for
more information.)