M17A1 Fire Control Quadrant

TM 9-1240-375-34&P

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LOCATION AND DESCRIPTION OF MAJOR COMPONENTS - Continued

M17A1 Fire Control Quadrant

M 17A1

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Fire Control Elevation Level Assembly (1). The fire control level assembly consists of an elevation level

vial in a vial holder. The fire control level assembly is used in checking the cannon in elevation.

Cover Assembly (2). The cover assembly of the M17A1 includes the counter windows, the light-

emitting diode (LED) light sources that illuminate the dials, and the battery enclosure assembly with

power switch.

Correction Knob Assembly (3). The correction knob assembly is located on the left side of the M17A1

quadrant. It is used to set elevation correction increments on the correction counter.

Counter Assembly (4). The counter assembly consists of the elevation counter and the correction

counter. The counters are mounted in the housing assembly.

Base Assembly (5). The base assembly provides the mounting surface for the M17A1 quadrant. It also

contains a bearing necessary for accurate rotation when setting elevation.

Worm Shaft Assembly (6). The worm shaft assembly is located internally and is controlled by the

elevation knob. The worm shaft assembly is used to level the M17A1 quadrant in elevation by moving

the elevation and correction counters.

Housing Assembly (7). The housing assembly for the M17A1 quadrant contains an elevation knob

assembly, correction knob assembly, counter assembly, fire control level assembly, and a worm shaft

assembly.

Battery Enclosure Assembly (8). The battery enclosure is located on the left front side of the M17A1

cover. It is used to hold the batteries and is equipped with a power switch.

Battery Power Switch (9). The power switch is located on the left side of the battery enclosure

assembly. It is used to cycle the battery power on and off. The power switch has a three-second delay.

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