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 514 of 775

TM 9-2350-311-10

3-7 FIRE CONTROL ALINEMENT TESTS AND MEASUREMENTS — CONTINUED

3-7.12

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Testing the M15 Elevation Quadrant and Auxiliary Quadrant (On M145/M145A1 Telescope Mount)

NOTE

Before doing this test you must level the gun trunnions. Zero the cannon tube.

Turn cross-level knob (1) on M15 elevation quadrant (2) until cross-level (3) bubble is centered.

Turn correction knob (4) on M15 elevation quadrant (2) and zero correction counters (5).

Turn the elevation knob (6) on M15 elevation quadrant (2) and center bubble in the elevation level (7).

Check elevation counter (8) reading. The reading should be less than 9999 (– 1 mil elevation) and no

more than 0001 (+1 mil elevation). If reading is not within tolerances, notify unit maintenance.

Place M1A1 gunner’s quadrant (9) on M15 elevation quadrant (2) seats (10). Apply the M1A1 gunner’s

quadrant correction factor, if any, but do not apply embedded correction.

Turn the micrometer knob (11) on M1A1 gunner’s quadrant (9) to center the bubble (12). The value of

the M1A1 gunner’s quadrant should not change more than 0.5 mil. If the value changes more than 0.5

mil, notify unit maintenance.

Example: M1A1 gunner’s quadrant correction is -0.4. The value on the M1A1 gunner’s quadrant should be

between -0.9 and +0.1.

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