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 179 of 590

5-5

TM

9-1240-401-34&P

Item No.

12

13

14

15

16

Item To Be Inspected

GUNNER’S AID COUNTER

RESET COUNTER

LENS

AZIMUTH COUNTER

COUNTER LEDS

Procedures

Rotate gunner’s aid knob (11) to stop in both directions.

Gunner’s aid counters (12) must have an excursion of 50 roils

in each direction before contacting stops at extremes.

Rotate reset counter knob (8) while observing reset counter (13).

Reset counter (13) must be able to reset to 3200 roils from any

counter position.

Rotate azimuth knob (10) while observing reset counter (13).

Reset counter (13) shall follow azimuth counter (15) within 0.25 mil

when azimuth knob (10) is rotated.

Set -50 roils on gunner's aid counter (12) (right) and check

that reset counter (13) reading increases by 50 ± 0.5 roils. Set

+50 roils on gunner's aid counter (12) (left) and check that

reset counter reading decreases by 50 ± 0.5 roils and that

azimuth counter (15) reading does not change.

Inspect lens (14) for dirt, fungus, or condensation which may

obstruct view through eyepiece; must be clean and

moisture free.

Rotate azimuth knob (10) clockwise, then counterclockwise

while observing azimuth counter (15). Azimuth counter (15)

indication must increase when azimuth knob (10) is rotated

clockwise and decrease when azimuth knob (10) is rotated

counterclockwise.

Rotate azimuth knob (10), gunner’s aid knob (11), and reset counter

knob (8) to lowest digit, with the lowest digit coinciding with its

respective index line. Check that remaining numbers are

in alinement within 1/16 inch (0.16 mm).

Inspect counter LEDs (16) by observing counter numerals;

numerals shall be clearly distinguishable in darkened area with

24 volts DC applied.