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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