TM 11-5840-281-35/1
Item No.
Trouble symptom
Probable trouble
Checks and corrective action
neous relay K4008 in Remote
or simultaneous relay K4008 in
Switching Control C-6989/TPN-18.
Remote Switching Control C-
6989/TPN-18.
c. Defective simultaneous mode
c. Check SCAN MODE switch S1102
control circuit from SCAN MODE
circuit in Pulse Generator O-
switch (on Pulse Generator 0-
1333/TPN-18.
1333/TPN-18 front panel) in master
Control-Indicator C-6988/TPN-18.
22 Abnormal elevation Antenna AS-
a. Defective scan control relays in
a. Refer to organizational antenna
1291/TPN-8 or azimuth Antenna
Remote Switching Control C-
control and data circuits
AS-1292/TPN-8 scan indications
6989/TPN-18.
troubleshooting chart in TM 11-
on precision scan beta displays or
5840-281-12.
search ppi scan displays.
b. Defective SCAN MODE switch (on
b. If Control-Indicators C-6988/TPN-
Pulse generator O-1333/TPN-18
18 are installed in Landing Control
front panel) in master Control-
Central AN/TSQ-71A, select other
Indicator C-6988/TPN-18.
Control-Indicator C-6988/TPN-18
as master by placing MASTER IND
select switch to 1 or 2, as
applicable to select other Control-
Indicator C-6988/TPN-18 as
master. If scans are normal, check
SCAN MODE switch circuit in
previously selected master Control-
Indicator C-6988/TP-18.
23 Height finder cursor abnormal or
Defective cursor control circuit card,
a. Replace cursor control circuit card
missing.
ALTITUDE control R1122, or EL
in applicable Pulse Generator 0-
CURSOR switch S1105 in
1333/ TPN-18. If condition still
applicable Pulse Generator O-
exists, perform b and c below.
1333/TPN-18.
b. Place EL CURSOR switch S1105
on applicable Pulse Generator 0-
1333/ TPN-18 to GP. If elevation
glide-path cursor and azimuth
course line cursor are normal,
perform c below. If elevation glide-
path cursor and azimuth course-
line cursor are also abnormal or
missing refer to item No. 26.
c. Check ALTITUDE control R1122
and EL CURSOR switch S1105 in
applicable Pulse Generator 0-
1333/TPN-18.
24 Elevation glide-path cursor
Defective CURSOR SELECT switch
a. Observe azimuth courseline cursor.
abnormal or missing.
S1104 or elevation glide-path
If azimuth courseline cursor is
cursor controls (TOUCHDOWN 1,
normal, perform b and c below. If
R1124;TOUCHDOWN 2,
azimuth courseline cursor is
R1125;GLIDEPATH 1, R1128;
abnormal or missing, refer to item
GLIDEPATH 2, R1181; GP VER 1,
No. 26.
R1129; and GP VER 2, R1130).
b. Check CURSOR SELECT switch
S1104 in applicable Pulse
Generator O-1333/TP-18.
c. If CURSOR SELECT switch S1104
is good, check TOUCH- DOWN 1
control R1124, TOUCH-DOWN 2
control R1125, GLIDE-PATH 1
control R1128, GLIDE-PATH 2
control R1181, GP VER1 control
R1129, and GP VER 2 control
R1130.
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