TM5-3820-256-10
3-21.
Troubleshooting Logging Equipment.
a. Set-up Test Set. A test set is provided so that you can check the instrument's operation independent of the cable
assembly. If the instrument reads the correct value for the test set, then the instrument itself is functioning
properly and the trouble is somewhere other than in the instrument's electronics. To sue the test set, plug it into
the instrument as described in 2-31, d. Then follow the operating instructions in paragraph 2-32, b. The
electrode selector must be in one of the NORMAL logging posit ions.
b. Checking Batteries. With the test set plugged into the instrument, turn the function switch to the CAL position
and try to calibrate the instrument:
(1)
If the instrument can be calibrated, then turn the function switch to CUR and check the current by throwing
the current switch; if the current flowing is less than 8 mA (full scale on meter is 25 mA), then the complete
set of six 9-volt batteries should be replaced (refer to figure 2-42).
(2)
If the instrument cannot be calibrated, the complete set of six 9-volt batteries should be replaced.
NOTE
Refer to battery voltage checking procedure to check the batteries with a voltmeter.
c. Troubleshooting. The following are commonly encountered troubles and the procedures to correct the problems.
Table 3-11. Troubleshooting the Logging Instrument
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
1.
UNABLE TO CALIBRATE
Step 1. Check for
If batteries low, replace. Make
INSTRUMENT.
low or no current.
sure lines and plugs are properly
connected.
Step 2. Test for
If galvanometer shows less than
high resistance at
9 mA, and it cannot be increas-
the steel surface
ed by rotating cal adjust knob,
of current elect-
then reduce resistance by driving
rode.
the stake in deeper, or pour
water around it, or by double
staking. If 8 mA cannot be
obtained, a situation not un-
common in thick dry sand or
where the ground is frost-cover-
ed, use the LATERAL arrange-
ment with CUR connected to
the well casing.
3-55
