TM 11-5840-281-35/1
Item No.
Trouble symptom
Probable trouble
Checks and corrective action
a. Check primary input power source
2 Low 6.8 vac heater voltage ...............
Low 120/208 vac primary input power.
b. Transformer
T101
in
Radar
Receiver-TransmitterRT-
818/TPN-18 defective.
3 Several dc supply voltages low
Check primary input power source.
Lower 120/208 vac primary input
Adjustment will not correct.
power
a.
a. Adjust 85v voltage regulator. Refer
4 Abnormal -35v or +35v supply
35v voltage regulator misaligned
voltages
to TM 11-5840-281-12 for
alignment instructions.
b.
b. Replace 85v voltage regulator circuit
Defective 35v voltage regulator
circuit card.
card and align as instructed in
TM 11-6840-281-12.
a.
a. Adjust +100v Power Supply PP-
5 Abnormal +100v supply voltage ..........
+100v
Power
Supply
PP-
3381/TPN-8 misaligned
3881/TPN-8. Refer to TM 11-
5840-281-12
for
alignment
b.
Defective +28v supply
instructions.
c.
b. Check +28v supply (step 8).
Defective +100v Power Supply
c. Replace +100v Power Supply PP-
PP-3381/TPN-8.
3381/TPN-8
and
align
as
instructed in TM-11-5840-281-12.
a. 200v Power Supply PP-3382/ TPN-8
a. Adjust 200v Power Supply PP-
6 Abnormal +200v or -200v supply
voltage.
misaligned.
3881/TPN-8. Refer to TM 11-
5840-281-12
for
alignment
instructions.
b.
b. Check +28v supply (step 8).
Defective +28v supply
c.
Defective 200v Power Supply PP-
Replace 200v Power Supply PP-
8882/ TPN-8.
3382/TPN-8
and
align
as
instructed in TM 11-5840-281-12.
a. Measure voltage at anode cap of tr
7 Abnormal keep-alive voltage at
Defective tr tube dropping resistor, or
tubes V101 and V1. Normal
anode cap of tr tube V101 or
-920v supply.
conduction of tr tubes should
V102.
maintain voltage between -200v
and -375v.
b. If keep-alive voltage is abnormal at
anode cap of V101 but normal on
anode cap of V102, check
resistance of dropping resistor
R108 (4.8 meg). If resistance of
R108 is correct, tr tube V101 is
defective.
c. If keep-alive voltage is abnormal at
anode cap of V102 but normal on
anode cap of V101, check
resistance of dropping resistor
R109 (4.8 meg). If resistance of
R109 is correct, tr tube V102
defective.
d. If keep-alive voltage is abnormal at
anode cap of V101 and V102,
the -920v supply (CR101,
CR102, and transformer T102) is
probably defective.
Refer to higher category maintenance.
8 Abnormal +28v supply ......................
Defective rectifiers CR115 thru CR120
a. Replace defective relay.
or transformer T103.
9 No azimuth-elevation relay gate
a. Defective 35 el relay K4006 or 60
at AZ-EL RELAY G testpoint
b. Replace defective switch
az relay K4009.
TP4003 on Remote Switching
b. Defective unblanking switch (8501,
Control
C-6989/TPN-18.
No
S02, or S508) in elevation
azimuth-elevation switching on
Antenna Drive TG-114/TPN-8 or
Control-Indicators C-988/TPN-18
unblanking
switches
displays.
(S1001,S1002, or S008) in
azimuth
3-3
Previous Page
