(12) Remove clinometer from elevation Antenna AS-
(7) Install top cover on elevation Antenna Drive
(8) Disconnect vtvm.
(9) On master Control-Indicator C-6988/TPN-18
3-21. Elevation Angle Data Potentiometer
Pulse Generator O-1333/TPN-18, place SCAN switch to
Electronic Filter Adjustment (fig. 3-23 and 3-24)
OFF, SCAN MODE switch to NORM, and ANGLE
VOLTS switch to OPERATE.
a. Test Equipment Required.
(10) Position elevation Antenna AS-1291/TPN-8 by
hand to scan angle of -1 degree as indicated on
(2) Clinometer MP3502 (clinometer).
clinometer. Maintain scan angle of -1 degree while
performing steps (11) and (12) below.
b. Equipment Conditions and Test Equipment
(11) With vtvm set for 100 volts, connect vtvm as
(1) Radar ,Set AN/TPN-18 turned on and radar set
(12) On elevation electronic filter, adjust OFFSET
(2) On master Control-Indicator C-6988/TPN-18,
control R705 to obtain an exact 0-volt indication on vtvm.
SCAN MODE switch placed to 35 EL.
Place RANGE switch on vtvm to progressively lower
ranges as required to achieve exact 0-volt indication.
18 control panel, SCAN and HV switch placed to OFF,
(13) Disconnect vtvm.
for safety of personnel.
(14) Replace cover removed in (4) above.
(4) Front cover (receiver side) of Radar Receiver-
Transmitter RT-818/TPN-18 removed.
3-22. Elevation 10- to 35- Degree Servo Actuator
(5) With vtvm set for 100 volts, connect as shown
a. Test Equipment, Tools, and Materials Required.
(1) Clinometer MP3502 (clinometer).
(2) Gage, feeler.
(1) Attach clinometer to clinometer mount on
(3) Sealing compound, Presstite 1175.25 or
(2) Remove screws and top cover at front of
elevation Antenna Drive TG-114/TPN-18 housing for
b. Equipment Conditions.
access to angle data potentiometer.
(1) Radar Set AN/TPN-18 turned on and radar set
(2) On master Control-Indicator C-6988/TPN-18
Elevation Antenna AS-1291/TPN-8 may be
Pulse Generator O-1333/TPN-18, SCAN MODE switch
positioned by hand by rotating knurled end of
placed to NORM.
drivemotor shaft located under cover on right end
18 control panel, SCAN and HV switches placed to OFF,
of elevation Antenna Drive TG-114/TPN-8
for safety of personnel.
(3) Positive elevation Antenna AS-1291/TPN-8 by
hand to dead bottom of its scan.
A second man is required to accomplish step (1)
(4) On vtvm, place RANGE switch to 10V and
SELECTOR switch to (-).
(5) Loosen locking screw in elevation camshaft
(1) Direct second man to place SCAN MODE
gear on outboard (left) end of camshaft. Rotate elevation
switch on master Pulse Generator 0-1333/TPN-18 to 35
angle data potentiometer drive gear until vtvm indicates -
EL. Stop 10-35 degree actuator at
(6) Tighten locking screw in camshaft gear.