TM 5-6675-307-14
Table 5-2. Troubleshooting-Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
5.
THEODOLITE WILL NOT TRAVEL VERTICALLY ON LINE
Step 1. Check theodolite for level.
Level theodolite.
a. Position theodolite on tripod head and secure with central fixing screw.
Step 2. Check for plate level or altitude level out of adjustment.
a. Adjust plate level as follows:
(1) Center circular level bubble using leveling screws.
(2) Position theodolite so that plate level bubble is as close to center as possible.
(3) Correct one-half of plate level bubble error with leveling screws.
(4) Adjust plate level capstan nuts until other half of error is removed.
(5) Turn theodolite 90 degrees and repeat Steps 3 and 4. Continue until bubble remains centered
in all positions of the theodolite.
b. Adjust altitude level as follows:
(1) Carefully level the theodolite and center altitude level with vertical tangent screw.
(2) With telescope direct, aim on a clearly defined target and record elevation angle.
(3) Transit telescope on its elevation axis, recheck centering of the altitude level bubble, and point
on same target. Record the elevation angle.
(4) The sum of the angles obtained in Steps 2 and 3 above should equal 360 + 0.1 minute.
(5) If deviation is more than 0.1 minute, perform the following adjustments:
(a) Divide the deviation obtained in b (2) and (3) by 2. This is the correction factor.
(b) Remove access screw and position bubble adjusting screw as follows:
1. If reading obtained in b (2) and (3) was more than 360 degrees and 0.1 minute.
subtract correction factor from vertical circle reading scale.
2. If reading obtained in b (2) and (3) was less than 359 degrees and 59.9 minutes,
add correction factor to the vertical circle reading scale.
(c) After adjusting, repeat test and replace access screw.
Step 3. Check for reticle out of adjustment.
Adjust reticle as follows:
a. Level theodolite, reverse telescope and aim at a well-defined point at least 330 feet away.
b. Transit telescope on its vertical axis and note point that appears on vertical cross line at about
same elevation and distance as first point.
c. Turn theodolite horizontally and aim at original point.
d. Transit telescope on its vertical axis. Vertical cross line should fall on second point. If it does not.
proceed as follows:
(1) Without changing position of theodolite after test, back off dust ring to expose four capstan
head reticle adjusting screws. Adjust screws until reticle vertical cross line moves one quarter
of the distance toward point observed.
(2) After obtaining proper distance, replace dust cap and repeat Steps a thru d.
6.
TELESCOPE COINCIDENCE LEVEL OUT OF LEVEL
Inspect to see if coincidence level is out of level.
Adjust coincidence (telescope) level as follows:
a. Carefully level the level with the vertical tangent screw.
b. Rotate the theodolite 180 degrees.
c. Correct one-half of coincidence level bubble with vertical tangent screw.
d. Adjust adjusting screws until other half of error is removed.
e. Rotate the theodolite 180 degrees and repeat Steps a, b, c and d. Continue until bubble remains
centered in all positions of theodolite.
7.
COMPASS WILL NOT OPERATE PROPERLY
Step 1. Check for compass not seating properly on compass bridge.
Replace compass.
Step 2. Check for compass reference mark not clearly visible or out of focus.
Clean reading prisms.
Step 3. Check if compass circle will not balance or rotate freely.
Replace compass pivot (para 5-15).
5-3
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