Lowrance X-28 Installation And Operation Instructions Manual page 22

Unit freezes, locks up, or operates erratically:
1. Electrical noise from the boat's motor, trolling motor, or an accessory
may be interfering with the sonar unit. Rerouting the power and transducer
cables away from other electrical wiring on the boat may help. Route the
sonar unit's power cable directly to the battery instead of through a fuse
block or ignition switch
2. Inspect the transducer cable for breaks, cuts, or pinched wires.
3. Check the transducer and power connector. Make certain it's securely
plugged in to the unit.
Weak bottom echo, digital readings erratic, or no fish signals:
1. Make certain transducer is pointing straight down. Clean the face of the
transducer. Oil, dirt, and fuel can cause a film to form on the transducer,
reducing its effectiveness. If the transducer is mounted inside the hull, be
sure it is shooting through only one layer of fiberglass and that it is securely
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bonded to the hull. Do NOT use RTV silicone rubber adhesive or Marinetex .
2. Electrical noise from the boat's motor can interfere with the sonar. This
causes the sonar to automatically increase its Discrimination or noise
rejection feature. This can cause the unit to eliminate weaker signals such
as fish or even structure from the display.
3. The water may be deeper than the sonar's ability to find the bottom. If
the sonar can't find the bottom signal while it's in the automatic mode, the
digital will flash continuously. It may change the range to limits far greater
than the water you are in. If this happens, place the unit in the manual mode,
then change the range to a realistic one, (for example, 0-100 feet) and
increase the sensitivity. As you move into shallower water, a bottom signal
should appear.
4. Check the battery voltage. If the voltage drops, the unit's transmitter
power also drops, reducing its ability to find the bottom or targets.
Bottom echo disappears at high speeds or erratic digital reading or
weak bottom echo while boat is moving
1. The transducer may be in turbulent water. It must be mounted in a
smooth flow of water in order for the sonar to work at all boat speeds. Air
bubbles in the water disrupt the sonar signals, interfering with its ability to
find the bottom or other targets. The technical term for this is 'Cavitation'.
2. Electrical noise from the boat's motor can interfere with the sonar. This
causes the sonar to automatically increase its Discrimination or noise
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