TM 11-5840-1-35/1
Item No.
Trouble symptom
Probable trouble
Checks and corrective action
34 Azimuth Antenna AS-1292/TPN-8
Perform precision scan mode
Azimuth synchro B1001 incorrectly
does not scan approximately 20
alignment (para 3-27).
nulled.
deg either side of 0 deg on
azimuth protractor, or scans a
sector 180 deg removed in NORM
scan mode.
Perform precision scan mode align-
35 Scan sequence in 35 EL precision
35-deg synchro B503 incorrectly
ment (para 3-27).
scan mode is other than azimuth
nulled.
ccw, elevation up, azimuth cw, and
elevation down.
Perform precision scan mode
36 Scan sequence in 60 AZ precision
10-deg synchro B502 incorrectly
alignment (para 3-27).
scan mode is other than azimuth
nulled.
ccw, elevation up, azimuth cw, and
elevation down.
Perform search scan mode
37 Blanked sectors on successive ppi
Antenna AS-1292/TPN-8 not rotating
alignment(para 3-26).
scan in SIMULT scan mode overlap
at 16 rpm.
each other.
a. Defective elevation motor speed
a. Replace defective relay.
38 Rate of scan is other than 80 cpm
control relay K4012, elevation
in NORM and 356 EL scan modes,
motor on-off relay K4007, scan on
or other than 15 cpm in 60 AZ
relay K4018, or associated circuitry
scan mode.
in Remote Switching Control C-
6988/TPN-18.
b. Defective drive motor B501 in
b. Refer to higher category of
elevation Antenna Drive TG-
maintenance.
114/TPN-8.
a. Synchros misaligned ..........................
a. Perform precision scan mode
39 Flashing or strobing on Control-
alignment (para 3-27).
Indicators C-6988/TPN-18 in
b. Defective azimuth elevation
b. Replace Remote Switching Control
precision scan modes (NORM,
switching relays K4015 or K4016 in
C-6989/TPN-18.
35EL, or 60 AZ).
Remote Switching Control C-
6989/TPN-18.
c Cams in azimuth Antenna Drive
c. Perform Antenna Drive TG-114/
TG-113/TPN-8 and elevation
TPN-8 cam alignment (para 3-20
Antenna Drive TG-114/TPN-8
and Antenna Drive TG-113/TPN-
misaligned.
cam alignment (para 3-23).
a. Check 10-35 deg elevation relay
a. Defective relays in Remote
K4005 and 35-deg elevation relay
40 Red connecting rod is not at top of
Switching Control C-6989/TPN-18
K4006 in Remote Switching Control
10-35 deg actuator slide when in 35
or defective 10-85 deg control
C-6989/TPN-18.
ELscan mode.
b. Perform elevation 10-35 deg
b. 10-35 deg actuator misadjusted or
actuator adjustments ( para 3-22). If
defective.
condition is not corrected by
adjustments, refer to higher
category maintenance.
Misaligned synchros ................................
Perform precision scan mode
41 Azimuth Antenna AS-1292/TPN-8
alignment (para 3-27).
does not scan approximately 20
deg cw to 50 deg ccw (referenced
from 0 deg on azimuth protractor)
when in 60 AZ scan mode.
3-1 1. Control-Indicator C-6988/TPN-18 Direct Support Troubleshooting Chart.
Item No.
Trouble symptom
Probable trouble
Checks and corrective action
a. Insure IFF ANT SCAN CONT
Defective iff interlock circuit ...............
1 Azimuth Antenna as-1292/tpn-18
will not synchronize with associate
switch S3201 in associated iff
iff antenna in SEARCH and
equipment is placed to RADAR.
b. Check precision relay K101 and iff
SIMULT scan modes
interlock relay K102 in Radar.
3-10
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