TM 11-5840-281-35/1
(3) Loosen three clamps holding azimuth angle
resulting in damage to actuator. Observe caution
data potentiometer and rotate potentiometer to obtain
to prevent running actuator beyond mechanical
indication of -8.7 volts on vtvm. Tighten three clamps.
limits.
(4) On master and slave Control-Indicators C-
6988/TPN-18, insure that ANGLE VOLTS switches are
NOTE
placed to OPERATE.
Retract limit microswitch is identified by red leads
(5) Disconnect vtvm. Place SELECTOR switch to
attached. Extend limit microswitch is identified by
(+), and connect vtvm as shown in figure 3-27 for
blue leads attached.
azimuth electronic filter adjustment.
(6) On azimuth electronic filter, adjust OFF-SET
(2) Attach clinometer to clinometer mount on
control R705 to obtain an exact 0-volt indication on vtvm.
azimuth Antenna AS-1292/TPN-8.
Place RANGE switch on vtvm to progressively lower
(3) Carefully tilt azimuth Antenna AS-1292/TPN-8
ranges to achieve exact 0-volt indication.
to +25 degrees as indicated on clinometer by placing
(7) Disconnect vtvm.
ANTENNA (servo) switch on master Control-Indicator C-
(8) Do not replace front cover (removed in b(1)
6988/TPN-18 to U or D as applicable. If azimuth Antenna
above) when additional alignments are to be performed.
AS-1292/TPN-8 stops short of +25 degrees, loosen
Allen-head screw in extend limit microswitch cam and
3-25. Antenna AS-1292/TPN-8 Antenna Tilt Actuator
move cam off of microswitch roller.
(4) Position cam so that it just actuates extend limit
microswitch. Tighten Allen-head screw in cam enough to
prevent cam from slipping.
a. Test Equipment Required.
(5) Carefully tilt azimuth Antenna AS-1292/TPN-8
(1) Clinometer MP3502 (clinometer).
down to -1 degree as indicated on clinometer by placing
(2) Multimeter ME-26A/U (vtvm).
ANTENNA (servo) switch on master Control-Indicator C-
6988/TPN-18 to D.
b. Equipment Conditions. Azimuth Antenna AS-
(6) Loosen Allen-head screw in retract limit
1292/TPN-8 antenna tilt actuator is aligned with the
microswitch cam and position cam so that it just actuates
equipment turned on, the radar set group level, and the
retract limit microswitch. Tighten Allen-head screw in
controls listed in (1) and (2) below placed to positions
cam enough to prevent cam from slipping.
indicated.
(7) Tilt azimuth AS-1292/TPN-8 up until extend
(1) On Radar Receiver-Transmitter RT-818/TPN-
limit microswitch actuates and stops azimuth Antenna
18 control panel:
AS-1292/TPN-8. Observe that azimuth Antenna AS-
(a) SCAN: OFF.
1292/TPN-8 stopped at +25 degrees as indicated on
(b) HV: OFF.
clinometer. If not, loosen Allen-head screw in extend limit
(2) On master Control-Indicator C-6988/TPN-18:
microswitch cam and make appropriate adjustment in
(a) SCAN MODE: SEARCH.
cam position.
(b) SCAN: OFF.
(8) Tilt azimuth Antenna AS-1292/TPN-8 down until
(c) TRANSMITTER: OFF.
retract limit microswitch actuates and stops azimuth
Antenna AS-1292/TPN-8. Observe that azimuth Antenna
c. Procedure.
AS-1292/PTN-8 stopped at -1 degree as indicated on
(1) Remove 10 screws that secure cover to
clinometer. If not, loosen Allen-head screw in retract limit
antenna tilt actuator and slide cover down on shaft to
microswitch cam and make appropriate adjustment in
expose adjustments. Exercise caution to prevent
cam position.
damage to cover gasket.
(9) Tighten Allen-head screws in retract and extend
limit microswitch cams securely.
CAUTION
(10) Position azimuth Antenna AS-1292/TPN-8 at
Antenna tilt actuator can be run beyond
exactly -1 degree as indicated on clinometer
mechanical limits during adjustments of retract
limit microswitch and extend limit microswitch,
3-32
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