TM 11-5840-281-35/1
(h) Vertical Presentation: CHANNEL
(3) At front of applicable Control-Indicator
A.
C-6988/TPN-18, Pulse Generator 0-1333/ TPN-18 pulled
(i) CHANNEL A AC-DC:DC.
out for access to top deck controls.
(j) CHANNEL A SENSITIVITY: As
(4) Rear cover removed from applicable
required.
Control-Indicator C-6988/TPN-18 for access to synchro
(k) CHANNEL A SENSITIVITY VER-
B602.
c. Procedure.
NIER: As required.
(7) Adjust INTENS BIAS control R2055 on
(1) On applicable Control-Indicator C-6988/
mixer amplifier and FOCUS and INTENSITY controls on
TPN-18, position heading overlay so that gridlines are
Control-Indicator C-6988/TPN-18 for a normal ppi
horizontal.
sweep.
(2) On Pulse Generator O-1333/TPN-18
(8) On Control-Indicator C-6988/TPN-18,
front panel, adjust ANGLE VOLTS control until sweep
rotate FOCUS control fully ccw, INTENSITY control fully
starts directly under center gridline.
cw, and AZ IF GAIN fully cw.
(3) On top deck of Pulse Generator 0-1333/
(9) On mixer amplifier, adjust INTENS BIAS
TPN-18, adjust PREC CENTER-HORIZ control R1136 to
control R2055 for maximum amplitude of intensity gate
position start of sweep 1/2 inch in from left edge of
on oscilloscope.
display.
(10) Disconnect oscilloscope.
(11) On Control-Indicator C-6988/TPN-18,
NOTE
rotate INTENSITY control fully ccw. Observe that sweep
on ppi display disappears.
If sweep start is not visible, increase sweep
(12) Adjust INTENSITY control and FOCUS
intensity by operating INTENSITY Control-
control for normal ppi sweep at normal operating level (at
Indicator C-6988/TPN-18 cw.
threshold of visibility).
(13) Adjust VIDEO GAIN control to desired
(4) At rear of Control-Indicator C-6988/
operating level of radar video.
TPN-18, loosen three screw clips holding synchro B602
(14) On mixer amplifier, when Radar Set
at top of deflection yoke assembly.
AN/TPN-18 is operated with Interrogator Set AN/TPX-44,
(5) While observing front of Control-
adjust IFF VIDEO control R2001 to desired operating
Indicator C-6988/TPN-18, rotate body of synchro B602 to
level of iff video.
position sweep trace horizontally beneath center gridline
(15) Replace rear cover on applicable
of overlay. Tighten three screw clips on synchro B602.
Control-Indicator C-6988/TPN-18.
Replace rear cover.
(6) On Pulse Generator O-1333/TPN-18
3-41. Ppi Display Alignment
front panel, rotate ANGLE VOLTS control fully ccw.
(7) On top deck of Pulse Generator 0-1333/
Refer to TM 11-5840-281-12 for the ppi display
TPN-18, adjust PREC CENTER VERT-AZ control R1106
alignment instructions.
The ppi display alignment
to position sweep trace under bottom gridline of overlay.
procedure aligns the ppi sweep gate length, sweep
(8) On Pulse Generator O-1333/TPN-18
expansion, and range mark amplitude controls.
front panel, place ANGLE VOLTS switch to EL.
(9) On top deck of Pulse Generator 0-1333/
TPN-18, adjust PREC CENTER VERT-EL control R1107
3-42. Precision Display Alignment
to position sweep trace 1/8 inch above center gridline of
overlay.
a. Test Equipment Required. None required.
(10) On Pulse Generator O-1333/TPN-18
b. Equipment Conditions.
front panel, set ANGLE VOLTS control to 220.
(1) Radar Set AN/TPN-18 turned ON.
(11) On top of deck of Pulse Generator O-
(2) On master Control-Indicator C-6988/
1333/TPN-18, adjust EXP-EL 10 control R114 to
TPN-18 and Pulse Generator 0-1333/TPN-18, SAN
position sweep trace under top gridline of overlay.
MODE switch placed to NORM, SCAN switch OFF,
TRANSMITTER switch OFF and ANGLE VOLTS switch
placed to AZ.
3-50
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