OPERATIONAL CHECKS

TM 5-6675-329-13 & P

Section III: OPERATIONAL CHECKS

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OPERATIONAL CHECKS

Operational checks, consisting of instrument leveling and focusing checks, are shown in Table 4-1. Perform the

procedures weekly when the instrument is in regular use. When the instrument is not used regularly, perform the

procedures before each use.

Table 4-1. Instrument Leveling and Focusing Checks

Operation

Normal Indication

Step

Corrective procedure

Level the telescope.

Circular level (8, Figure 1-2) bubble remains centered when instrument is rotated through

360

Set up Tripod Assembly GST-40 so that its legs are stable and firmly planted

on (or in) the ground, in an as near level position as possible.

With Automatic Level NA2-80 mounted on Tripod, turn the horizontal drive

knob(s) to rotate level through 360 in the horizontal plane, while matching

circular level bubble through prism. Bubble should remain centered through

360 of rotation. If not, readjust footscrews(s) at level positions(s) where it

goes off center, and re-rotate level until bubble remains centered throughout

continuous rotation. Press the test pushbutton (7, Figure 1-2) while looking

through the telescope. The telescope image should momentarily move off

center and then come back to the centered position. This assures the level

compensator mechanism is functioning properly.

Focus crosshairs.

When instrument is focused reticle crosshairs appear sharp and absolutely black (See

Point instrument to a uniformly lighted surface or a sheet of white paper.

Rotate eyepiece (Figure 1-2, item 6) until above normal indication is obtained.

Image Focusing.

Image (usually a leveling staff) is sharp and free from parallax with respect to reticle

crosshairs.

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