TM-9-1240-400-34&P Technical Manual for M109 Telescopes and Mounts Download
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TM 9-1240-400-34&P 6 Measure distance from head assembly (4) to mark on wall in inches (centimeters). 7 Multiply distance in step 6 by 0.30350 (tangent of 300 mils). 8 Place tape (5) (item 14, appx C), above and below mark, at distance determined in step 7. 9 Rotate elevation knob (6) from stop-to-stop. Reticle must follow plumbline within 0.5 mil. Line of sight must elevate, or depress, no less than 300 mils. 10 If plumb travel is not within limits, replace prism assembly. Refer to page 2-50. 11 If line of sight travel is not within limits, adjust elevation knob. Refer to page 2-71. ELEVATION MECHANISM BACKLASH 1 Aline reticles by turning elevation knob (1), clockwise, without overtravel. 2 Check that micrometer (2) is zeroed. 3 If not, loosen three screws (3) and turn micrometer (2) so that index points to "0". Tighten three screws. 4 Rotate elevation knob (1), counterclockwise, at least a half turn, and return clockwise with no overtravel to aline index to zero. 5 If reticles are not within 5.0 mils, adjust head assembly. Refer to page 2-57. 2-71