TM-9-2350-311-10

HOWITZER, MEDIUM, SELF-PROPELLED, 155MM; M109A2, M109A3, M109A4 AND M109A5

TECHNICAL MANUAL; OPERATOR’S MANUAL

NOVEMBER 1994

TM-9-2350-311-10 - Page 512 of 775

TM 9-2350-311-10

3-7 FIRE CONTROL ALINEMENT TESTS AND MEASUREMENTS — CONTINUED

3-7.10

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8

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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.

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