Geokon 1300, Instruction Manual

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11
5. TROUBLESHOOTING
Consult the following list of problems and possible solutions should difficulties arise. Consult
the factory for additional troubleshooting help.
Symptom: Transducer Readings are Unstable

Is the readout box position set correctly? If using a datalogger to record readings
automatically are the swept frequency excitation settings correct? Try reading the transducer
on a different readout position. For instance, channel A of the GK-401 and GK-403 might be
able to read the transducer. To convert the Channel A period display to digits use Equation
1.

Is there a source of electrical noise nearby? Most probable sources of electrical noise are
motors, generators, transformers, arc welders and antennas. Make sure the shield drain wire
is connected to ground whether using a portable readout or datalogger. If using the GK-401
Readout connect the clip with the green boot to the bare shield drain wire of the pressure cell
cable. If using the GK-403 connect the clip with the blue boot to the shield drain wire.

Has the transducer gone outside its range? This may happen in either compression or
extension. Check the previous readings for any trends. The extensometer may be need to be
re-installed in the borehole, see section 2.

Does the readout work with another transducer? If not, the readout may have a low battery
or be malfunctioning. Consult the appropriate readout manual for charging or
troubleshooting directions.
Symptom: Transducer Fails to Read

Is the cable cut or crushed? This can be checked with an ohmmeter. Nominal resistance
between the two gage leads (usually red and black leads) is 180

,

10

. Remember to add
cable resistance when checking (22 AWG stranded copper leads are approximately 14.7

/1000' or 48.5

/km, multiply by 2 for both directions). If the resistance reads infinite, or
very high (megohms), a cut wire must be suspected. If the resistance reads very low (

100

) a short in the cable is likely.

Does the readout or datalogger work with another transducer? If not, the readout or
datalogger may be malfunctioning. Consult the readout or datalogger manual for further
direction.
Sympton: Transducer will not hold pressure

Check all the fittings on the pneumatic lines using a soap solution and observe for bubbles. If
no leaks are found then the O-ring on the anchor piston may be cut or nicked. Replace the O-ring
using one of the spares from the accessories supplied with the equipment. The piston is held
inside the anchor by a small “ding” made by a prick punch. This has to be filed off with a round
file so that the piston can be pushed out. Replace the O-ring and then push the piston back into
place and again “ding” the end of the hole with a hammer and screwdriver so that the piston is
once again held in place.