Section IV. TROUBLESHOOTING
74. General
81. Plate Level Bubble Does Not Stay in Center
Probable cause
Possible remedy
This section provides information useful in
Leveling screws loose or
Adjust or replace screws
diagnosing and correcting unsatisfactory operation or
worn.
failure of the theodolite and its components. Each
Plate level bubble jumps ...... Replace level vial (par. 97).
trouble symptom stated is followed by a list of probable
82. Collimation Level Bubble Does Not Stay in Center
causes of trouble. The possible remedy recommended
Probable cause
Possible remedy
is described opposite the probable cause.
Level mounting loose .......... Tighten screws (par. 93).
75. Theodolite Will Not Seat Properly on Tripod
Level bearing binds ............. Clean bearing (par. 93).
Head
Level bubble jumps ............. Replace level vial (par. 93).
Probable cause
Possible remedy
83. Illumination System Fails To Function
Star plate defective .............. Replace or repair the star
Probable cause
Possible remedy
plate (par. 95).
Wiring defective
Repair or replace wiring
76. Theodolite Will Not Stay on Line
(pars. 128 and 129).
Probable cause
Possible remedy
Faulty contact between
Clean ring or clean and
Vertical travel off line ........... Line up right side axis
U-standard contact and
straighten points (par.
bearing (par. 122).
contact ring due to bent
115).
Excessive right side axis
Aline or replace axis bear-
or dirty points and ring.
bearing side play.
ing (par. 122).
Illumination socket defec-
Replace socket (par. 119).
Star plate loose or defec-
Tighten, replace, or repair
tive.
tive.
star plate (par. 95).
Battery box rheostat de-
Replace rheostat (par. 128).
77. Leveling Screws Too Tight or Too Loose
fective.
Probable cause
Possible remedy
Battery box defective .......... Repair or replace battery
Leveling screws dirty or
Clean, repair, or replace
box (par. 128).
worn.
leveling screws (par.
84. Horizontal Circle Has Unequal Light or No Light
Probable cause
Possible remedy
Leveling screws out of
Adjust leveling screws
Illumination system de-
Refer to paragraph 83.
adjustment.
fective.
78. Telescope Turns Too Hard or Too Easily
Illumination prism dirty,
Clean, tighten, or replace
Probable cause
Possible remedy
fogged, etched, or loose.
prism (par. 110).
Right side axis bearing
Replace axis bearing (par.
85. Vertical Circle Has Unequal Light or No Light
defective.
122).
Probable cause
Possible remedy
Telescope axis worn............. Replace axis (par. 123).
Illumination system de-
Refer to paragraph 83.
79. Horizontal Circle Hard To Move
fective.
Probable cause
Possible remedy
Inverter prism dirty,
Clean, tighten, or replace
Horizontal circle drive de-
Repair, replace, or adjust
loose, or etched.
prism (par. 100).
fective or out of adjust-
circle drive (par. 118).
86. Horizontal Circle Graduations Unequal
ment.
Probable cause
Possible remedy
Circle drive teeth dirty or
Clean, repair, or replace
Illumination prism im-
Reinstall or replace prism
worn.
circle drive teeth (pars.
properly installed or
115 and 118).
defective.
80. Plate Level Vial Defective
87. Horizontal Circle Graduations Not at Right
Probable cause
Possible remedy
Angles to Line Dividing the Two Images
Defective bubble ................. Replace vial (par. 97).
Probable cause
Possible remedy
Level vial broken ................. Replace vial (par. 97).
Horizontal circle prism
Adjust horizontal prism
carrier too loose or
carrier (par. 111).
too tight.
55
AGO 5078A
