DATASONICS SIS-1500 System Manual page 94

5-12
The VOLTS meter indicates
a voltage that is less than
140 volts, and/or the
AMPERES meter shows no
current fluctuations or a
current over 500 ma.
(Cont.)
Volume I System Manual
Table 5-2 Tow Vehicle Activation Problems
Symptom
The deck cable or the
armored coaxial tow cable is
faulty.
(Cont.)
The Power board in the sonar
electronics is not functioning
or one of the other circuit
boards is faulty.
Possible Cause
DATASONICS
Corrective Action
The voltage should read
greater than 140 volts, and
the current should deflect to a
peak value for about
2 seconds, settle to about
300 ma, and then pulse at
four times a second. If the
proper readings are not
observed, refer to Cable
Checks on page 5-19 and
check the cable.
In the electronics housing, if
none of the LEDs on the
Backplane board are
illuminated, check the output
of the Melcher DC Regulator
for 48 VDC. If 48 VDC is not
present, check the input for
144 VDC. If 144 VDC is
present, replace the
regulator. If 144 VDC is not
present, replace the Cable
Interface board.
If one or more, but not all of
the LEDs on the Backplane
board are not illuminated,
remove all of the boards from
the Backplane board with the
exception of the Power board.
In addition, disconnect the
wire harness that connects
the Transmitter and Receiver
boards to the Backplane
board. If one or more of the
LEDs still are not illuminated,
replace the Power board.
If all the Backplane board
LEDs are illuminated when all
the boards are disconnected,
reinsert each board (and
reconnect the wire harness),
one at a time, while observing
the Backplane board LEDs. If
any of the LEDs extinguish,
replace the last board
inserted or connected.
June 1998