TM-9-2350-311-10 M109 Operator's Manual for M109A2, M109A3, M109A4 and M109A5 Download
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TM 9--2350--311--10 3--36 3--6 ARMAMENT AND CAB MAINTENANCE 3--6.1 Maintenance of Sighting and Fire Control Equipment a. Inspection Whenever inaccuracies, maladjustments, or other conditions affecting the serviceability are evident, the equipment should be referred to unit maintenance. Check instruments for completeness and appearance. Painted surfaces should be free of wear, scratches, or chipped or loose paint. All graduations, lettering, and indexes must be clear and distinct. There must not be evidence of corrosion on any part. There must be no dirt, smears, stains, scratches, digs, condensation, fungus growth, chips, fractures, or cement separations visible through optics. b. Care Rough or careless handling can cause inaccuracy of the sighting and fire control instruments. The following points will keep your equipment in working order: 1 Don’t force rotation of any knob beyond its stop limit. WARNING Don’t point an optical instrument directly at the sun without using a filter. The heat of focused rays may damage eyes and optical elements. 2 Keep instruments as dry as possible. If wet, dry before stowing in carrying case. Condensation may collect on optical parts when temperature of parts is lower than surrounding air. Moisture can be removed by placing instruments in a warm, but not hot place. Heat can cause unequal expansion of parts, resulting in damaged optics. CAUTION • To prevent damage to components, under no circumstances should polishing liquids, pastes, or abrasives be used for polishing lenses and windows. • For wiping optical parts, use lens paper (item 33, Appx D) especially intended for cleaning optical glass. To prevent damage to components, don’t use silicone treated paper that is used for eyeglasses. 3 Keep optical parts free of oil and grease. Don’t touch lenses or windows with fingers. To remove oil or grease from optical surfaces, apply optical lens cleaning compound (item 9, Appx D). If cleaning compound is not available, and temperature is above freezing, breathe heavily upon glass and wipe off with clean lens paper (item 33, Appx D).