Section VI: MAINTENANCE PROCEDURES

TM 5-6675-329-13 & P

Section VI: MAINTENANCE PROCEDURES

4-10 GENERAL

Circular Level (8, Figure 1-2)

The Tripod Assembly with Automatic Level NA2 attached, is set up on firm ground. Using the three

footscrews (2, Figure 1-2), the bubble is centered exactly in the middle of the setting circle. The instrument is now

rotated through 180". If the bubble is displaced so that it no longer lies within the setting circle, it should be adjusted.

When doing this, the bubble's glass cover must not be touched with the finger. Half of the bubble displacement is taken

out with the footscrews and the other half with the two adjustment screws (Figure 4-1) using the adjusting pin kept in the

Carrying Case NA2-80. As an adjustment screw is tightened the bubble runs towards it and, as it is loosened, the bubble

runs away from it. The first adjustment screw to be turned, therefore, is the one that is the nearest to being in line with

the middle of the bubble and the center of the setting circle. It is turned only until the bubble reaches the center of the

circle or until it can be set in the center by means of the other screw. The screws must not be turned more than is

necessary to complete the adjustment.

Figure 4-1. Adjusting the Circular Level

4-8