TM-9-1240-401-34&P Technical Manual for M109 Telescopes and Mounts Download
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4-53 TM 9-1240-401-34&P d. QUADRANT SUPPORT ASSEMBLY ADJUSTMENT 2 3 4 5 6 7 8 9 10 11 12 1 Clamp a 3/8- by 3/4- by 6-inch parallel bar (1) to quadrant seat of bracket parallel to the quadrant support assembly level (2). Position a zeroed M1A1 gunner’s quadrant (3) on parallel bar (1), parallel to quadrant support level (2). Adjust quadrant support assembly level knob (4) until gunner’s quadrant level (5) bubble is centered. Remove threaded ring (6) using fabricated eccen- tric tool (fig. C-3, appx C). Apply sealing compound to threaded ring (6) and install in bracket. Engage fabricated eccentric tool in holder (7) and threaded ring (6). Insert a common straight blade screwdriver through the center hole in the fabricated eccentric tool (fig. C-3, appx C) and engage control cam (8). Adjust control cam (8) and threaded ring (6) until the level (2) bubble is centered within the gradu- ations on the level (2). Rotate cross-leveling fixture (9) from 0 to 1330 mils and adjust control cam (8) and threaded ring (6) until the level (2) bubble is centered within the graduations on the level (2). Rotate cross-level fixture (9) from 1330 mils to 0 and adjust control cam (8) and threaded ring (6) until the level (2) bubble is centered within the graduations on the level (2). Repeat steps 9 and 10 as necessary to center level (2) bubble at 0 and 1330 mils. Hold the inner portion of the fabricated eccentric tool (fig. C-3, appx C) firmly in place while turning the outer portion of the tool to tighten threaded ring (6). Be careful not to disturb the setting of level (2).