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 3-7 FIRE CONTROL ALINEMENT TESTS AND MEASUREMENTS — CONTINUED 3-7.10 7 8 9 10 Scribe Verification Using the M145/M145A1 Telescope Mount Check — Continued Look through the eyepiece (4) on the M117/M117A2 panoramic telescope (5) again and find the same reference point (7). Be sure to move the head of the M117/M117A2 panoramic telescope from left to right. If the sight is off to the right of the reference point, turn the head of the M117/M117A2 panoramic telescope at least 50 mils in the opposite direction and reapproach the reference point from left to right to eliminate any induced backlash. Record the reading that is on the azimuth counter (8). NOTE The difference between the two readings taken on the azimuth counter (steps 4 and 8) should not be over ± 1 mil. If it is, notify unit maintenance to check the M145/M145A1 telescope mount. However, for purposes of this test, the ± 1 mil tolerance is not critical. The difference in the readings on the azimuth counter (8) at zero mil (step 4) and 900 mils elevation (step 8) is the amount of error in the M145/M145A1 telescope mount (3). Record the amount of error in the M145/M145A1 telescope mount (3). It will be needed later. The accuracy of the scribe lines on the M15 elevation quadrant (9) are now verified. 3-108