Lowrance M68C IceMachine, Installation And Operation Instructions Manual

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Section 6:
Sonar Troubleshooting
If your unit is not working, or if you need technical help, please use the
following troubleshooting section before contacting the factory customer
service department. It may save you the trouble of returning your unit
for repair. For contact information, refer to the last page, just inside the
back cover of this manual.
Unit won't turn on:
1. Check the power cable's connection at the unit. Also check the wiring.
2. Make sure the power cable is wired properly. The red wire connects
to the positive battery terminal, black to negative or ground.
3. Check the fuse.
4. Measure the battery voltage at the unit's power connector. It should
be at least 10 volts. If it isn't, the wiring to the unit is defective, the
battery terminals or wiring on the terminals are corroded, or the bat-
tery needs charging.
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 trans-
ducer 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 sure it's securely
plugged in to the unit.
Weak bottom echo, digital readings erratic, or no fish signals:
1. Make sure the transducer is pointing straight down. Clean the face of
the transducer. Oil, dirt and fuel can cause a film to form on the trans-
ducer, 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 bonded to the hull. When attaching a transducer to the inside
of a hull, ONLY use the epoxy available from LEI (order information is
inside the back cover). Do NOT use RTV silicone rubber adhesive or any
other type of epoxy. The LEI epoxy is specially formulated so that it will
cure properly for shoot-through applications.
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.