TM-9-2350-311-20-2 Maintenance Manual Volume 2 for M109 Cab Download
Page 84 of 828
TM 9–2350–311–20–2 Change 1 2–23 Table 2-2. PREVENTIVE MAINTENANCE CHECKS AND SERVICES FOR M109 SELF- PROPELLED HOWITZER Location Item No. Interval Item to Check/Service Procedure Not Fully Mission Capable if: 1 Quarterly Mount M145/M145A1 Check synchronization (para 18–4). 2 Quarterly a. M117/M117A2 Telescope Purge quarterly (TM 750–116). Purge im- mediately if moisture is found in units be- fore quarterly service date. WARNING The M1A1 collimator is radioactively illuminated. Check for presence of illumination and dam- age. If discovered broken, damaged, or defective, follow the procedures listed on page b. b. M1A1 Collimator c. M118A2/M118A3 Elbow Telescope d. M15 Elevation Quadrant WARNING The M140 alinement device is radioactively illuminated. Check for loss of luminescence, break- age, damage, or defects. If present, follow the procedures on page b. e. M140 Alinement Device f. M42 Tank Periscope WARNING 3 Quarterly Fire Control Instruments Failure to aline reticle of M140 aline- ment device with reticles of M117/M117A2 panoramic telescope and M118A2/M118A3 elbow telescope using boresighting procedure could result in projectiles landing outside tar- get area. Injury or death of friendly forces can result from firing with misalined fire control equipment. Perform boresighting on target board, alining reticles of M117/M117A2 panoram- ic telescope and M118A2/M118A3 elbow telescope on test target board. Next, in- stall the M140 alinement device in front of each sighting and fire control instrument (M117/M117A2 panoramic telescope and M118A2/M118A3 elbow telescope) to en- sure that reticle of the M140 alinement device coincides with the reticles of the M117/M117A2 panoramic telescope. This check must be performed to ensure accu- racy of the M140 alinement device (TM 9–2350–311–10).