TM 11-5840-281-35/1
Item No.
Trouble symptom
Probable trouble
Checks and corrective action
a. Defective antenna circular polarizer
a. Replace antenna circular polarizer
20 Neither ANT POL LIN indicator or
ANT POL CIR indicator lights.
relay K4019 in Remote Switching
relay K4019.
Control C-6989/TPN-18.
b. Defective lamps
b. Depress ANT POL LIN and ANT
POL CIR indicators to test indicator
lamps.
c. If ANT POL switch on master
c. Defective slip-ring assembly E1001
in azimuth Antenna Drive TG-
Control-Indicator C-6988/TPN-18 is
113/TPN-8 or azimuth polarizer
placed to LIN, simulate slip-ring
switch S9802 circuit in azimuth
assembly and azimuth polarizer
polarzer.
switch S9302 circuit by disconnect
in connector P1001 on azimuth
Antenna Drive TG-113/TPN-8 and
connecting jumper wire between
pins G and J on connector P1001.
ANT POL LIN indicator will light if
trouble
is
defective
slip-ring
assembly E1001 or azimuth
polarizer switch S9302 circuit. If
ANT POL switch on master
Control-Indicator C-6988/'TPN-18
is placed to CIR, simulate slip-ring
assembly and azimuth polarizer
switch
S9301
circuit
by
disconnecting connector P1001 on
azimuth
Antenna
Drive
TG-
113/TPN-8 and connecting jumper
wire between pins H and K on
connector P1001. ANT POL CIR
indicator well light if trouble is
defective slip-ring assembly E1001
or azimuth polarizer switch S9301
circuit.
d. Defective elevation polarizer switch
d. If ANT POL switch on master
S9201 circuit in elevation polrizer.
Control-Indicator C-6988/TPN-18 is
placed to LIN, simulate polarizer
switch
S9201
circuit
by
disconnecting connector P501 on
elevation Antenna Drive TG-
114/TPN-8 and connecting jumper
wire between pins J and m on
connector P501. ANT POL LIN
indicator will light if trouble is
defective elevation polarizer switch
S9201 circuit.
If ANT POL switch on master
Control-Indicator C-6988/TPN-18 is
placed to CIR, simulate polarizer
switch
S9204
circuit
by
disconnecting connector P501 on
elevation Antenna Drive TG-
114/'TPN-8 and connecting jumper
wire between pins K and N on
connector P501. ANT POL CIR
indicator will light if trouble is
defective elevation polarizer switch
S9201 circuit.
a. Defective simultaneous relay KI103
a. Replace simultaneous relay K1003
21 Master Control Indictor C-
(on Pulse Generator 18333/TPN-18
in slave Control-Indicator C-
6988/TPN-1S has precision beta
front panel) in slave Control-
6988/TPN-18.
scan but slave Control-Indicator C-
Indicator C-6988/TPN-18.
6988/TPN-18 does not have search
b. Defective simultaneous ppi
b. Check simultaneous ppi elevation
ppi scanwhen in SIMULT scan
elevation switching relay K4014
switching relay K4014 and simulta-
mode.
3-13
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