(7)
Place control panel switches in following positions:
(a)
Mode/function selector switch - STBY (standby)
(b)
System transfer switch - 1
(c)
Gain control - AUTO or NORM
(d)
Antenna TILT control - 14 degrees UP.
(e)
Antenna stabilization switch (if provided) - ANT STAB
(8)
Place controls on both indicators in following positions:
(a)
RANGE - set to max range indicated on test pattern (fig. 501).
(b)
BRT or BRIGHTNESS - fully CCW (minimum)
(c)
Display offset control (if provided) - AHEAD (center).
(d)
On AT ALL,
SCAN/HOLD control - SCAN.
(9)
Select TEST mode on control panel. Test pattern will appear after warmup period of approximately 3 minutes is completed.
(10)
Adjust the BRT/BRIGHTNESS control on the indicators for presentation of range marks.
(11)
AF 157, 161, LOCATION OF RANGE MARKS TOTAL NUMBER OF RANGE DISPLAYED RANGE MARKS DISPLAYED
50 20, 40 2 100 20, 40, 60, 80, 100 5 200 50, 100, 150, 200 4
AZ 201-224, LOCATION OF RANGE MARKS TOTAL NUMBER OF RANGE DISPLAYED RANGE MARKS DISPLAYED
50 25, 50 2 150 50, 100, 150 3 300 50, 100, 150, 200, 250, 300 6
IB 406-499; AZ 231-280, XA LH ALL LOCATION OF RANGE MARKS TOTAL NUMBER OF
RANGE DISPLAYED RANGE MARKS DISPLAYED 30 10, 20, 30 3 80 25, 50, 75 3
180 25, 50, 75, 100, 125, 150, 7 175 300 50, 100, 150, 200, 250, 300 6 XA AZ 225-229, 281-299, LOCATION OF RANGE MARKS TOTAL NUMBER OF
RANGE DISPLAYED RANGE MARKS DISPLAYED 30 10, 20, 30 3 80 20, 40, 60, 80 4
180 30, 60, 90, 120, 150, 180 6 300 50, 100, 150, 200, 250, 300 6
(12)
Set RANGE to maximum range shown on test pattern (Fig. 501).
(13)
AF 157, 161; AZ 201-224,
(a) Set display offset control to LT position. Observe that apex of display shifts right.
EFFECTIVITY
AT ALL; AZ ALL; LH ALL; CONFIG 1 AF 157, 161; IB 406-499 ATG A Page 502 Sep 25/94
34-43-00
(b)
Set display offset control to RT position. Observe that apex of display shifts left.
(c)
Set display offset control to AHEAD position. Observe display is symmetrical about the center of indicator.
(14)
On AT ALL (PPI-IN indicators with SCAN/HOLD switch)
(a)
Set SCAN/HOLD switch to HOLD on each indicator. The existing video on each indicator will not be updated with new video information.
(b)
Set SCAN/HOLD switch to SCAN. The video on each indicator will be updated.
(15)
On AT ALL; LH ALL; IB 406-499; AZ 231-280, observe the test pattern on each indicator. Adjust BRT control to obtain test pattern conforming to Fig. 501. If satisfactory test pattern cannot be attained, refer to trouble shooting section.
(a)
The display from 0 to 50 nautical miles should be composed of two bright video bands separated by contoured (dark) central area. A malfunction in either the R/T or antenna which activates the T/R or ANT fault lamp(s) on the R/T will also cause the disappearance of the video test band in the TEST mode.
(b)
The display from 50 to 100 nautical miles should be dark with light noise evident just prior to 100 mile range mark. This display sector indicates an operational STC circuit.
(c)
The test signal is displayed from approximately 100 nautical miles to edge of scope. With tunnel diode amplifier (TDA) off, noise should not be visible. When TDA is on, heavy noise will appear. Display of light noise, when TDA is off indicates a malfunction and loss of sensitivity.
(16)
AF 157, 161; AZ 201-224, observe the test pattern on each indicator. Rotate BRIGHTNESS controls to clockwise to obtain test pattern in Fig. 501. If satisfactory test pattern cannot be attained, refer to trouble shooting section.
(a) Observe a bright snowy band across the indicator between 25 NM and 60 NM.
NOTE: The BRIGHTNESS control should be adjusted so that the
____ noise or "grass" (small specks of light resembling snow) is absent behind the 25 NM range mark, but then appears and becomes progressively brighter reading outward to the iso-contour arc at 60 NM.
(b) Observe indicator for two bright solid bands between 70 and 100 NM, which indicate one test video target. Observe dark band (iso-contour) between these bright bands.
XA (17) On AZ 225-229, 281-299, observe the test pattern on each indicator. Rotate BRT controls to clockwise to obtain test pattern in Fig. 501. If satisfactory test pattern cannot be attained, refer to trouble shooting section.
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