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4200 SIDE SCAN SONAR SYSTEM USER HARDWARE MANUAL 0004842_REV_N
3. Check that the cards installed on the topside electronics are properly seated and that any attached
cables are connected, especially if the unit has been in transit. Cards and cables can be checked
visually by opening the top cover of the topside. If the problem persists, disengage, and then
reengage all PC boards. Do the same for all board cable connections, before going on to any
electrical testing.
4. Check the system’s calibration. All calibration adjustments are preset at the factory and should
not require any modifications in the field unless certain mechanical and/or electrical components
are changed, or the adjustments are inadvertently altered. Please contact E
DGETECH CUSTOMER
SERVICE to learn what the default settings are and instructions on how to reset or change them.
5. Ensure that any optional internal or external components aren’t causing the problem by
disconnecting them from the system.
If the above checks do not identify or remedy the problem, attempt to isolate the failure to one of the
major system components: the sonar processor, the modem/power unit, the towfish, or the tow
cable.
The following sections provide some specific areas to check and easily identifiable clues 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.
5.5.1 Required Equipment
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
5.5.2 Transmission Verification
The 4200 series tow fish differs from the conventional side scan sonars used for many years. The early
sonars were driven with a high-powered energy burst similar to hitting a bell with a hammer. The 4200
series transducers are driven with a smooth rising lower power signal that matches the transducer
response. Because of this, there is no pronounced clicking noise emanating from the 4200’s transducers
when they are firing. Therefore the ‘listen for the clicking noise’ test cannot be used to verify sonar
transmission during bench or on-deck testing.
Sniffing with an oscilloscope can be used as a substitute to check transducer firing. One way is to attach
the scope probe’s ground to the tow fish body and hold the open probe next to the transducer under test.
Set to about 20 to 50mV /Div.
A second method is to connect a several-turn wire loop across the scope probe and move it over the
transducer face. Electrical pickup should be noticed on the scope screen at each transmission burst.
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