TM-9-1240-400-34&P Technical Manual for M109 Telescopes and Mounts Download
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TM 9-1240-400-34&P ITEM ITEM T0 NO. BE INSPECTED PROCEDURE -- Plumb Travel (Elevation Travel) Establish telescope line of sight through intersection of reticle line coincident to plumb line target image, that will accommodate +300 mil excursion of line of sight from horizontal position. Elevate and depress l line of sight 300 mils from horizontal by means of elevation knob. Any deviation of line of sight from plumb line image during each excursion shall not exceed 0.5 mil. -- Collimation Set deflection and reset counters to indicate 3200 mils by use of appropriate control knobs Line of sight through intersection of telescope reticle lines shall not deviate from vertical target line more than 0.5 mil, as measured on projector collimator test reticle. NOTE: With panoramic telescope set up as described above, the following tests can be performed simultaneously. -- Deflection Error Error at deflection readings in 800 mil increments, (800 Mil Steps) through at least 2 full revolutions of head, shall not exceed 1.5 mil, including backlash. Total spread between greatest positive error and greatest negative error shall not exceed 1.5 mil. Total error including backlash, between the deflection counter and reset counter reading for any one number, shall not exceed 0.5 mil. -- Deflection Error This test should be conducted concurrent with test (15 Mil Steps) specified above. Rotate gunner’s aid knob until 15 mils are added to reset counter. Error at deflection counter in 15 mil increments of reset counter shall not exceed 0.25 mil, excluding backlash. -- Level Travel Establish telescope line of sight horizontal with refer- ence to flat horizontal mounting surface keyways and pivot point elevation of 90-degree prism Position horizontal target line coincident to telescope line of sight. Rotate telescope head through 2 revolutions by means of deflection knob, while simultaneously rotating telescope through 2 revolutions in opposite direction, by means of testing device. During this excursion, any vertical deviation of line of sight from horizontal target line shall not exceed 1.0 mil per revolution (total excursion of 2.0 mils) as measured on projector collimator test reticle. Level travel shall be tested at minimum of eight 800-mil deflection (azimuth) settings. 2-7