Section VI
Paragraphs 6-53 to 6-59
used to align the phase localizer for the previously
e. Adjust the MICROVOLTS dialto duplicate the avc
voltage read in step b above. Dial will read approxi-
determined positions of the localizer sectors and cen-
ter setting of the control knob. The 30 CPS m o d u l a -
mately 1000 microvolt.
tion level and 30~ LEVEL SET control must be ad-
justed prior to the
LOC CENTER and LEVEL con-
f. With AUDIO SELECTOR in VOR position and the
trol adjustments.
VOR switch in 0 position adjust VOR ZERO control
a. Connect the Ballantine electronic voltmeter to the
tered. The TO-FROM indication will be TO.
AUDIO OUT connector of Signal Generator SG-13/ARN.
6-54. VOR TRACKING ADJUSTMENT. The VOR
Set MEGACYCLES control to 110.1 mc, adjust SET
LINE TO 21V, METER ZERO, and CARRIER SET
tracking adjustment must be preceded by the VOR
controls.
ZERO adjustment. Carry out adjustments given in
b. Turn AUDIO SELECTOR to the 30~ VAR
posi-
below.
tion and note the 30 cps voltage obtained at the AUDIO
a. Set up Signal Generator SG-l/ARN to read 500
OUT connector. It should be approximately 0.65 volts.
microvolt at 114.9 mc and modulate it at 30 percent
with the VOR signal from Modulator MD- 83 A/ARN.
c. Turn AUDIO SELECTOR to
LOC position and
Connect output of Signal Generator SC-l/ARN to input
ground the junction of C1424 and C1425 to render the
of the navigation receiver.
9960 FM oscillator inoperative. See figure 6-11.
b. Set the PHASE ANGLE SELECTOR on Modulator
MD-83A/ARN to 90. Center the microammeter by
d. Turn the LOC-GS control to the right and set the
setting the COURSE on ID-249A/ARN to approximately
knob center line on the top engraved line of the right
hand sector.
90 with the SET control. Do not change this SET
control setting.
e. Set the
LOC LEVEL control to obtain a voltage
c. Substitute Signal Generator SG-13/ARN for Sig-
reading on the Ballantine voltmeter which is 38 per-
nal Generator SG-l/ARN and Modulator MD-83A/ARN.
cent of the voltage noted above in the 30 ~ VAR
po-
Set MEGACYCLES dial to 114.9 mc and adjust CAR-
sition. With the 9960 FM oscillator still inoperative
RIER SET control for red line indication. Turn VOR
set the LOC-GS cent rol to the middle of the white cen-
switch to 90.
ter sector engraved on the panel and adjust the
LOC
CENTER control for a null reading of the meter. Re-
d. Adjust VOR TRACK control (figure 6-11) for ex-
check the
LOC LEVEL control and readjust if nec-
act centering of the microammeter. The TO-FROM
essary. Turning the LOC-GS control to the top en-
indication will be TO.
graved line of left sector, a voltage reading will be
obtained which is the same as the top line of the right
e. Recheck the VOR ZERO adjustment as outlined in
hand sector if the two sectors have been very care-
fully adjusted as instructed in paragraph 6-50. Lock
on Modulator MD-83A/ARN set to 180 and note the
the controls.
error between 0 and 180. If this error exceeds
0.75 readjust VOR ZERO control to add or subtract
6-56. LUBRICATION.
half the error from 0.
f. Recheck the VOR TRACK adjustment given in
6-57. The signal generator must be lubricated at
steps a through d above with the PHASE ANGLE SE-
least every 500 hours as given in Section V, para-
LECTOR on Modulator MD-83A/ARN set to 270 and
graph 5-17.
note the error between 90 and 270. If this error
exceeds 0. 75 readjust VOR TRACK control to add or
subtract half the error from 90. After both the VOR
ZERO and VOR TRACK adjustments are made, lock
both controls.
6-59. The signal generator should be inspected peri-
odically to prolong service life and assure continued
6-55. PHASE LOCALIZER ADJUSTMENT. PHASE
operation of the equipment. Refer to Section V, para-
LOC CENTER and LEVEL controls (figure 6-11) are
graphs 5-19 through 5-22 for inspection schedule.
