GLF
05-08-2006, 08:52 PM
Electrical noise usually affects the display with many black dots at high speeds and high sensitivity readings. One or more of the following sources can cause noise or interference:
Possible source of noise
Other electronic devices
How to isolate it
Turn off any nearby electronic devices to see if the problem goes away. Then turn them on one at a time to see if the noise reappears.
Possible source of noise
The boats engine
How to isolate it
To determine whether the boats engine is the source of the noise, increase the RPMs while the boat is in neutral and stationary to see if the noise increases proportionately. If the noise appears when you rev the engine, the problem could be the spark plugs, alternator or tachometer wiring. replace the spark plugs with resistor plugs, install an alternator filter, or route the control head power and transducer cables away from engine wiring.
Possible source of noise
Cavitation from the boats propeller(s)
How to isolate it
Turbulence created by the propeller can cause noise. make sure the transducer is mounted at least 15" from the propeller, and that the water flows smoothly over the face of the transducer at all times.
Possible source of noise
Other electronic devices
How to isolate it
Turn off any nearby electronic devices to see if the problem goes away. Then turn them on one at a time to see if the noise reappears.
Possible source of noise
The boats engine
How to isolate it
To determine whether the boats engine is the source of the noise, increase the RPMs while the boat is in neutral and stationary to see if the noise increases proportionately. If the noise appears when you rev the engine, the problem could be the spark plugs, alternator or tachometer wiring. replace the spark plugs with resistor plugs, install an alternator filter, or route the control head power and transducer cables away from engine wiring.
Possible source of noise
Cavitation from the boats propeller(s)
How to isolate it
Turbulence created by the propeller can cause noise. make sure the transducer is mounted at least 15" from the propeller, and that the water flows smoothly over the face of the transducer at all times.