Document: 990-0000046-1000
Page
14
4
4
2
2
0
0
0
0
-
-
F
F
S
S
S
S
i
i
d
d
e
e
S
S
c
c
a
a
n
n
S
S
o
o
n
n
a
a
r
r
7.1.4
T
RANSDUCER
R
EMOVAL
Transducers may be inspected, repaired, or replaced without dismantling the towfish housing.
1.
Remove the tail cone assembly as above
2.
Disconnect the set of transducer connectors from the end cap. Mark them to assist in
reassembly. Also refer to Figures 7-2 and 7-3.
3.
Remove the eight hex-head mounting bolts for the transducer cover, and remove the
transducer cover.
4.
Remove the transducer mounting nuts (8mm) and washers for the transducer element in
question and slide it off the towfish body-mount studs. Note and preserve the order of
the nuts, washers and rubber grommets when disassembling the unit.
Note: Both port and starboard transducer elements are identical
5.
When replacing a transducer, fit new rubber grommets to the transducer assembly prior
to mounting. Place the grommets on the array first
without
using any lubricant. Lightly
lubricate the mounting studs on the towfish body using silicone grease.
6.
Make sure the order of the washers and nuts are preserved as noted in step 4 above,
when re-assembling the unit. Do not over tighten the mounting nuts. Use a straight
edge along the face of the arrays to preserve horizontal alignment. The maximum
deviation should be less than 2mm over the full length of the 2 transducers.
7.2
T
ROUBLESHOOTING
The 4200-FS towfish is a computer controlled device. Therefore in order to troubleshoot such a
complex piece of equipment to a sub-module level, one must have the proper test equipment and
thorough knowledge of the unit’s electrical operation plus hardware aspects. The purpose of this
section is not to develop those techniques nor provide a step-by-step procedure where one may
start and end up at the point of failure. It is to give an operator some familiarity with the
electronic hardware. The following sections provide some specific areas to check which are
easily identifiable and certain clues as to what to look for in making an educated guess as to the
source of the problem. This is only down to the module or PCB level.
7.2.1
E
QUIPMENT
R
EQUIRED
Except for the topside processor/power unit, only common laboratory test equipment and tools
are required for field troubleshooting. No special equipment is necessary. Typical test equipment
includes:
•
Digital multi-meter
Fluke, or equivalent
•
Oscilloscope
•
Hi-pot tester
•
Capacitance meter
