TM 9-1240-400-34&P
ITEM
ITEM T0
NO.
BE INSPECTED
PROCEDURE
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Plumb Travel (Elevation Travel)
Establish telescope line of sight through intersection
of reticle line coincident to plumb line target image,
that will accommodate +300 mil excursion of line of
sight from horizontal position. Elevate and depress
l
line of sight 300 mils from horizontal by means of
elevation knob. Any deviation of line of sight from
plumb line image during each excursion shall not
exceed 0.5 mil.
--
Set deflection and reset counters to indicate 3200
mils by use of appropriate control knobs Line of
sight through intersection of telescope reticle lines
shall not deviate from vertical target line more than
0.5 mil, as measured on projector collimator test
reticle.
NOTE: With panoramic telescope set up as described above, the following tests can be
performed simultaneously.
--
Deflection Error
Error at deflection readings in 800 mil increments,
(800 Mil Steps)
through at least 2 full revolutions of head, shall not
exceed 1.5 mil, including backlash. Total spread
between greatest positive error and greatest negative
error shall not exceed 1.5 mil. Total error including
backlash, between the deflection counter and reset
counter reading for any one number, shall not exceed
0.5 mil.
--
Deflection Error
This test should be conducted concurrent with test
(15 Mil Steps)
specified above. Rotate gunner's aid knob until 15
mils are added to reset counter. Error at deflection
counter in 15 mil increments of reset counter shall not
exceed 0.25 mil, excluding backlash.
--
Level Travel
Establish telescope line of sight horizontal with refer-
ence to flat horizontal mounting surface keyways and
pivot point elevation of 90-degree prism Position
horizontal target line coincident to telescope line of
sight. Rotate telescope head through 2 revolutions
by means of deflection knob, while simultaneously
rotating telescope through 2 revolutions in opposite
direction, by means of testing device. During this
excursion, any vertical deviation of line of sight from
horizontal target line shall not exceed 1.0 mil per
revolution (total excursion of 2.0 mils) as measured
on projector collimator test reticle. Level travel shall
be tested at minimum of eight 800-mil deflection
(azimuth) settings.
2-7
