Unit installation

FS70 Trawl Sonar System
60 974-24007001/4.1
4.3.20 Final System Test
After preparing the trawl cable and before the final trawl unit
assembly a system test should be conducted to insure correct
operation of the FS 70 Trawl Monitoring System over the trawl
cable.
As before, the start- up procedures should be followed to power up
the system. Once the FS 70 has been turned on, the power supply
voltage and current meters should be examined. Expected values are
0.2 – 0.5 A, (output voltage selection switch should be set to
200VDC). If the voltage and current values differ significantly from
these values, it indicates a problem with the trawl cable or its
connections.
If there are any errors during the calibration a status report page will
appear containing the results that the control unit obtained from the
tests performed. Again, any errors will be due to the trawl cable or
its connections. Check the connections again and ensure that the
signal polarity at the trawl unit is correct. A DC voltmeter can be
used to check that the positive voltage is on the small pin of the
pigtail when the FS PWR/TTM unit is powered up.
If all is okay then the sonar head will begin scanning and the sonar
image display will appear.
4.3.21 Completing the Trawl Unit Assembly
First, the plastic cable strain relief supplied with the trawl unit must
be bolted to the trawl cable. The location should be at or very near
the pigtail splice, but NOT on the pigtail itself. You must slide the
rubber hose on the trawl cable, if used, down so that approximately
3.4 cm (1’.2") of the hose is clamped inside the strain relief.
Next, the trawl cable is connected to the sonar head. Liberal amounts
of Dow Corning #55 grease are applied to the connector surfaces
before mating so that a water tight seal is obtained. The locking
sleeve is then hand-tightened.
NOTE: Dow Corning “#55” grease must be applied to all
mating surfaces of underwater connectors to insure proper
sealing. Sufficient grease should be applied so that excess
squeezes out with any air when the connectors are mated. RTV
or any other sealant must NOT be used, and when tightening
the locking sleeves do NOT use a wrench or pliers!