TM-9-1240-401-34-P

TELESCOPE MOUNT M146: M118A2 AND M118A3; TELESCOPE MOUNT M145: M145A1; PANORAMIC TELESCOPE: M117 AND M117A2; FIRE CONTROL QUADRANT: M15; PERISCOPE: M42

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL

JULY 1993

TM-9-1240-401-34-P - Page 167 of 590

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TM 9-1240-401-34&P

d. QUADRANT SUPPORT ASSEMBLY ADJUSTMENT

2

3

4

5

6

7

8

9

10

11

12

1

Clamp a 3/8- by 3/4- by 6-inch parallel bar (1) to

quadrant seat of bracket parallel to the quadrant

support assembly level (2).

Position a zeroed M1A1 gunner’s quadrant (3) on

parallel bar (1), parallel to quadrant support level

(2).

Adjust quadrant support assembly level knob (4)

until gunner’s quadrant level (5) bubble is centered.

Remove threaded ring (6) using fabricated eccen-

tric tool (fig. C-3, appx C).

Apply sealing compound to threaded ring (6) and

install in bracket.

Engage fabricated eccentric tool in holder (7) and

threaded ring (6).

Insert a common straight blade screwdriver

through the center hole in the fabricated eccentric

tool (fig. C-3, appx C) and engage control cam (8).

Adjust control cam (8) and threaded ring (6) until

the level (2) bubble is centered within the gradu-

ations on the level (2).

Rotate cross-leveling fixture (9) from 0 to 1330 mils

and adjust control cam (8) and threaded ring (6)

until the level (2) bubble is centered within the

graduations on the level (2).

Rotate cross-level fixture (9) from 1330 mils to 0

and adjust control cam (8) and threaded ring (6)

until the level (2) bubble is centered within the

graduations on the level (2).

Repeat steps 9 and 10 as necessary to center level

(2) bubble at 0 and 1330 mils.

Hold the inner portion of the fabricated eccentric

tool (fig. C-3, appx C) firmly in place while turning

the outer portion of the tool to tighten threaded ring

(6). Be careful not to disturb the setting of level (2).