TM 11-5840-35/1
AS-1292/TPN-8.
When tilt-servo ANTENNA switch
turned on by the positive signal to its base and transistor
S602 is operated to RIGHT, relay K4002 applies +28
Q4012 is turned on by the negative-going signal from the
volts to the right winding of the servo actuator. When the
collector of transistor Q4011. When transistor Q4011
switch is operated to UP, K4003 applies +28 volts to the
conducts, all the az-el switching relays are operated to
up winding of the tilt actuator on Antenna AS-1291/TPN-
switch all precision circuitry to elevation. When the
8; and when operated to DOWN, relay K4004 applies
elevation scan is completed and its microswitch rolls off
+28 volts to the down winding of the tilt actuator.
the cam, the elevation trigger is produced in the same
(7) When relay K406 is operated by SCAN
manner as the azimuth trigger to change the state of
MODE switch S1102 on Control-Indicator C-6988/TPN-
transistors Q4009 and Q4010, and turn off transistors
18, contacts 1 and 2 operate relay K4005, which applies
Q4011 and Q4012. The az-el switching relays are
+28 volts to the 35-degree winding of the 10 to 35-
restored, and all functions switch to azimuth. When
degree actuator on Antenna Drive TG-114TPN-8. When
operating in the SEARCH mode, the base of transistor
relay K4005 is restored, +28 volts are applied to the 10-
Q4012 is returned to +28 volts through the contacts of
degree winding of the actuator.
operated relay K4007. The +28 volts cuts off transistor
(8) The +28 volt actuator power is applied
Q4012 and all az-el switching relays remain restored,
to relays K4001 through K4005 through fuse F4001 (fig.
thus, preventing any elevation function from being
7-37). Should any of the limit switches on the actuators
utilized.
fail, fuse F4001 will blow before the actuator can
(11) The unblanking gate (or scan blanking
overheat. Indicator DS4001 lights when fuse F4001 is
pulse) is generated by the same microswitches which
blown. If indicator DS4001 is lighted, the faulty limit
produce the azimuth and elevation triggers.
switch must be located and corrected.
When the microswitches are riding the appropriate
(9) An az-el relay gate is produced in all
elevation or azimuth cams, the scans are unblanked by
precision modes, and switch circuits in Radar Receiver-
the switches grounding the positive voltage which
Transmitter RT-818/TPN-18 and Control-Indicator C-
originates in the video mixer.
6988/TPN-18 between the azimuth and elevation
(12) In the SIMULT mode of operation,
function during the respective scan periods. Azimuth
Antenna AS-1292/TPN-8 functions the same as for
and elevation gates are produced to unblank the
search operation.
Antenna AS-1291/TPN-8 also
indicator crt during antenna sector controlled by
operates continuously, and the az-el switching relay is
microswitches operated by camshafts in Antenna Drive
controlled to display 2 out of 3 elevation scan sectors
TG-113/TPN-8 and Antenna Drive TG-114/TPN-8 (fig.
(unless one of the elevation sectors is in, or closely
precedes, the azimuth display sector).
(10) The az-el relay gate, generated by a
(a) Azimuth is displayed each time the search
transistor relay gate circuit, consists of bistable
antenna scans through the 30-degree precision azimuth
multivibrator transistors Q4009 and Q4010, and inverter
sector. SIMULT relay K4008 is operated in simultaneous
amplifier transistors Q4011 and Q4012 located in
operation and provides a ground for unblanking the ppi
Remote Switching Control C-6989/ TPN-18. See the
display except when EIM PPI-EL SWITCHING relay
simplified schematic (fig. 2-18) of the trigger circuit for
K4014 is operated to present elevation signals. Slave
the az-el relay gate multivibrator. The 47,000-ohm
Control-Indicator C-6988/TPN-18 displays search signals
resistor, the 220,000ohm resistor and the 0.082-uf
except when blanked by relay K4014. Master Control-
capacitor represent either resistors R4037 and R4038
Indicator C-6988 'TPN-18 displays only the precision
and capacitor C4006, or resistors R4046 and R4047 and
azimuth sector of the ppi signals, and the elevation
capacitor C4007. During the scan of Antenna AS-1292/
signals.
Relay K4008 also connects the azimuth
TPN-8, capacitor C4006 charges to -35 volts. As the
unblanking gates to Control-Indicator C-6988 'TPN-18
microswitch rolls off the cam, the capacitor is grounded
when relay K4014 is operated. Relay K4014 is operated
at its negative end to produce a positive pulse to trigger
each time an elevation scan is to be presented and
the multivibrator (or to turn transistors Q4009 off and
produces an artificial azimuth relay gate trigger and
Q4010 on). When transistor Q4010 is turned on,
closes the elevation unblanking gate circuit to Control-
transistor Q4011 is also
Indicator C-6988 TPN-18.
(b) Relay K4014 is operated by the two
2-29
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