TM 11-5840-281-12-1
4-27. PRELIMINARY SERVICING AND ADJUSTMENT. (CONT)
9.
Set ART ANGLE V control on pulse generator to indicate 15 divisions less than indication recorded in step 5.
NOTE
ART ANGLE V control is now set to produce a - 1.5 degree artificial sweep trace.
10.
Alternately place ANGLE VOLTS switch in AZ and OPERATE positions. Adjust R38 EL WIDTH control on AZ-
EL blanking pulse generator card so bottom edge of blanked rangemark section coincides with - 1.5 degree
artificial sweep trace.
11.
Ensure ANGLE VOLTS switch is returned to OPERATE position.
4-28. CIRCUIT ALINEMENT.
This paragraph contains procedures for locating target simulators on radar display; performing precision display
adjustments; alining azimuth, elevation, and height finder cursors; and adjusting and orientating ppi display. After target
simulators are located on radar display, three cursors (azimuth, elevation, and height finder) are alined by comparison
with two points of intercept which are represented by predetermined settings of ART ANGLE V control. The settings of
ART ANGLE V control are determined by azimuth offset angle, elevation ground angle, and elevation alinement angle.
These angles are determined before the actual cursor alinements. Lastly, ppi display is oriented to airfield using azimuth
range and bearings of three fixed targets. Prior to performing circuit alinements, obtain the following data to avoid
delays:
Field elevation
Runway headings
Glide scope angle
Azimuth range and bearings of three fixed targets.
PRECISION DISPLAY ADJUSTMENTS
NOTE
Unless otherwise indicated, perform the following steps on control-indicator where precision
display adjustments are being performed.
1.
On both pulse generators, place SCAN MODE switch to NORM position.
2.
On master pulse generator, place SCAN switch to OFF position.
3.
On control-indicator, turn navigational grid on display so grid lines are horizontal.
4.
On pulse generator, place ANGLE VOLTS switch to AZ position. Adjust ART ANGLE V control to position
artificial sweep directly under center grid line.
5.
Loosen two front panel captive head screws on pulse generator and pull pulse generator out of control-indicator
to expose top deck controls and circuit cards.
6.
On top deck of pulse generator, adjust PREC CENTER-HORIZ control to position start of artificial sweep 1/2 inch
from left edge of display.
7.
Check that sweep is parallel to center grid line. If not, refer to a higher category of maintenance.
4-85
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