Edgetech 2000-CSS, User Manual

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6-12 6.0: TROUBLESHOOTING
2000-CSS COMBINED SONAR 0017423_REV_C
R1+R2 =_______________
2. Remove the shorts.
3. Measure the resistance between a shorted pair on one end with an ohmmeter on the Rx1 scale.
R1+Rs =_______________
4.
Measure the resistance from the other end.
R2+Rs =_______________
5. Add the measurements of 4) and 5) above, subtract the measurement of 2), and divide the result
by 2.
Rs =_________________
6. Subtract the value of 6) from the measured values of 4) and 5).
R1 =_________________
R2 =_________________
7. The distance to the short from end #1 is the ratio of (R1/R1+R2) times the total cable length.
Recheck from end #2 which is (R2/R1+R2) times the cable length.
6.3.8.2 Open Wire
An open wire in a cable is much more difficult to locate than a short circuit; therefore, a capacitance bridge
is recommended. Measuring the capacitance from the open wire to the shield on both ends allows two
different capacitance readings to be recorded. This represents a direct ratio related to cable length and
distance of break from each end. Before cutting the cable, double-check the same ratio of capacitance
using an adjacent good wire in a multi-conductor cable. Capacitance may vary from wire to wire,
depending on their separation.
Most breaks occur around the tow cable termination or where a previous repair has been made. A cable
break may be found or confirmed by laying out the cable and attaching an ohmmeter across each end of
the open wire. Then flex the cable first near the termination or repaired section and then along its entire
length until the break is reached. When flexing, the ends of the broken wire may touch, giving a continuity
reading on the meter.
6.3.8.3 Insulation Resistance Breakdown
Insulation breakdown is the most difficult fault to locate. Cable leakage is not necessarily located near
the end terminations. However, the area near each termination receives the most abuse and is, therefore,