Testing In Air Without Paravane Receiver - Furuno CN-24 Service Manual

NOTE:
1) Stop the transmission within 5 minutes to prevent damage of transducer
2)The unit of 10 W TX output can not be checked in air The test can be done by one of
two ways.
•
Reduce the output power down to 2.4Wand follow the procedures on page 4-4.
•
Place the TX unit in the water tank or bucket and check the operation. If signal
transmitting transducer is working, you can hear the TX sound and sense the
pressure on the transducer surface by hand. The display check can not be done
with this method.
2. Rotate the screw of the pressure switch (test switch) clockwise with a screwdriver to turn
on the transmitter unit.
3. Placing your finger on the radiating face, you can feel pulses if the transmission is made
normally.
4. Turn on the display unit.
If all units (transmitter, receiver + cable and display unit) are operating satisfactory, some
echoes are displayed on the screen. Note that the depth of echoes is four times greater
than their actual depth since sound velocity in air is a quarter of the one in water.
5. If the operation check results are satisfactory, turn the test switch fully counterclockwise.
3.2.2 Test in Air without Paravane Receiver
Make the test cable and place the loop on the signal transmitting transducer as show in
figure 7.3. The signal from the transducer can be picked up through the loop by the
electromagnetic induction.
Fig. 3.3 Testing function in Air without Paravane Receiver
3-3