Onwa KF-667 - Manual (Page 31)

4.3 Transducer Check
A simple and reliable check of the transducer is to temporarily replace the transducer with a new
one. If the sensitivity is considerably improved through this change, the transducer is probably
faulty. This method is especially useful for inside-hull or through-hull installation.
Another method is to listen to the transmission sound. Haul the transducer from the water and
turn on the power. Put your ear near the transducer face and carefully listen to the transmission
sound. If you can hear a clicking sound, the transducer is probably normal. Next, rub the
transducer face with your hand and observer whether noise appears on the screen. The
appearance of noise indicates the transducer is normal. In case of neither sound nor noise, the
transducer is probably faulty.
4.4 Water Temperature Sensor (option) Check
The idea of the transducer check can apply to this case, too; temporarily substitute a new sensor.
If the temperature indications become normal, your sensor may be faulty.
When a new sensor is not available, the water temperature indication should change when you
touch the thermosensor.
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