TM 11-6625-3025-14/ET426-AA-MMA-010/E154 VII210/T.O. 33A1-8-902-1-1
(7) Set the controls to display the number of elements desired in the position desired. The position of the V
bar elements is variable by use of the H position control at the front panel. Check that the control range
changes position in the pattern slightly more than a distance equal to the width between elements at all
settings of the HSPACING control Leave the H position control set at mid-range, because this control
will vary the number of V
(8) The number of V bar elements generated in the horizontal tv line is variable by use of the H SPACING
control at the front panel. Check control range. The number of elements displayed will depend on the
scan rate being used because the length of horizontal line is different for various scan rates. At the 675-
line rate, typical range is from 5 to 35 elements.
(9) Set oscilloscope B delayed sweep to 0.1 usec per division and adjust the sweep delay time to show one
dot element .Adjust the size of the V bar elements with the V bar size control (R25 on the V bar card,
figure 6-12). This also adjusts the size of the dot elements in the dot pattern. Set the control to obtain V
bar element width at 0.10 usec pulse width +0.05 usec. Return oscilloscope to A sweep (undelayed) .
(10) Set pattern switch to BLACK. Set oscilloscope sweep to 2 msec. Compare oscilloscope display to
(11) Observe the video portion of the signal while turning the VIDEO LEVEL control from 0 to 10. Video
amplitude should vary from 0.0v to 1.0v peak-to-peak +0.10v. The sync and blanking portions of the
composite video signal should remain at the levels set in flat field.
(12) Set oscilloscope sweep to 2 msec. Connect the oscilloscope external sync to the V drive source.
Compare oscilloscope display to figure 6-11b.
(13) Connect the video G connector to the monitor input to view the V bar pattern. Check that the V bars are
straight, a white pattern on a black background. Select BLACK pattern, which should provide a black V
bar pattern on a white background. Return pattern switch to WHITE.
(14) Performance verification of the V bar function is now complete.
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