TM-9-1240-400-34-P

TELESCOPE; PANORAMIC: M115, ELBOW: M139, MOUNT: M138 AND M137

TECHNICAL MANUAL; DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL

OCTOBER 1993

TM-9-1240-400-34-P - Page 223 of 344

TM 9-1240-400-34&P

CHECKING ILLUMINATION OF M137 TELESCOPE MOUNT

1

Perform the illumination inspection with M137

telescope mount in a darkened area and connected to

any suitable 24-volt d.c.

power sup- ply.

2

With 24 volts d.c.

applied to the M137 telescope

mount power source connector (1), turn variable

resistor knob (2) between minimum and maximum

illumination and observe that lamp (3) in extension

light (4) brightens and dims.

3

Place toggle switch (5) to ON and observe that vial

and counter lights (6) illuminate.

The illumination

shall be sufficient for level vial markings and counter

numbers to be clearly defined.

Place toggle switch

(5) to OFF.

CHECKING M137 TELESCOPE MOUNT RIGIDITY

Apply a 20.0-lb (9.1-kg) load with spring tester gage to

right side of upper assembly.

Release load and record.

Repeat on left side of upper assembly.

Movement shall

not exceed 0.25 mils at 0 mils, 0.75 mils at 800 mils,

1.75 mils at 1100 mils, and 3.50 mils at 1333 mils.

If

requirements

cannot

be

met,

check

for

loose

components.

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