TM 11-5840-360-14-1-1
14. Set MONITOR SEL ECT switch to HV and
given in paragraph 5.17.3.3 must be
verify green zone reading on test meter M1. Leave
checked and performed as required
MONITOR SELECT switch al HV through step 17
upon completion of step 37.
following .
15. Connect oscilloscope, Set for approximately -10
Table 5-5. Receiver Transmitter RT-1241 Power
Vdc measurement, at control panel HV SAMPLE TP9.
Supply Test Points
16. Set LOCAL PRF SELECTOR switch alternately
POSITIVE
NEGATIVE
DC
between SHORT and MED, noting the dc voltage level
LEAD
LEAD
VOLTAGE
displayed on the oscilloscope for each position.
TP1
TP10
+5.1 0.25
17 Adjust LOAD COMP control A2A4R29 until the
TP2
TP10
+12.0 0.5
voltage difference observed between SHORT and MED
TP3
TP10
+12.0 0.5
is 0.1 Vdc or less.
TP10
TP4
-12.0 0.5
18. Repeat steps 12 and 13 above.
TP5
TP10
+120 10
19. Set LOCAL. TEST switch to OFF.
TP10
TP6
- 550 50
20. Turn off all ships circuit breakers which supply
TP9
TP10
+11.8 0.5
power to Receiver Transmitter RT- 1241.
5.17.3.3 Transmitter Circuits Adjustment (V4) . The
21. Connect variac between ships 115Vac input
following procedure provides instructions for adjustment
cable and FL1 and FL2. Ground variac to equipment
chassis.
pulse widths of the modulator drive pulse generators
22. Connect multimeter, set to 250 Vac scale,
and final adjustment of the modulator bias and high
between FL1 and FL2 inputs; maintain connection
voltage levels.
through step 32 following.
NOTE
23. Set ships circuit breakers which supply power to
Observe the settings of Switching
Receiver Transmitter RT-1241 to ON.
Units SA-2139 and refer to Table 3-3
24. Adjust variac for 120 Vac reading on multimeter
to determine which Indicator is
.
serving as master for Receiver
25. Connect second multimeter, set for 10 Vdc
Transmitter RT-1241 (MTR 11).
scale, between A2A5E3 (+} and chassis (-) .
1. At Receiver Transmitter RT-1241:
26. Set LOCAL TEST switch to ON. After 3minute
a. Set LOCAL TEST switch to REMOTE
time delay, verify second multimeter reads +5.0 +
ENABLE .
0.5Vdc.
b. Set LOCAL PRF SELECTOR to
27. Turn BIAS VOLT control A2A5R7 fully
REMOTE.
counterclockwise.
2. At master Indicator:
28. Adjust variac to reduce reading to first
a. Set POWER switch to TX ON.
multimeter to 114 Vac.
b. Set RANGE SELECT switch to 1.5 MILES
29. Carefully adjust BIAS VOLT control A2A5R7
3. At Receiver Transmitter RT-1241, connect
clockwise just until reading on second multimeter drops
oscilloscope, set for 2 volts and 50 usec per division, at
to zero Vdc.
J5 TRIGGER jack; adjust oscilloscope for display of two
30. Adjust variac to reduce reading on first
negative-going trigger pulses.
multimeter to 80 Vac. Second multimeter reading
4. Carefully note the time between positive
should remain at zero Vdc.
[trailing) edges of the trigger pulses.
31. Carefully adjust BIAS VOLT control A2A5R7
5. At Receiver Transmitter RT-1241:
counterclockwise just until reading on first multimeter
a. Set LOCAL TEST switch to ON.
jumps to + 5.0 0.5 VDC.
b. Set LOCAL PRF SELECTOR switch to
32. Set LOCAL. TEST switch to OFF.
SHORT .
33. Turn off all ships circuit breakers which supply
power to Receiver Transmitter RT 1241.
34. Disconnect variac and restore normal cable
connections at FL1 and FL2 inputs.
35. Set ships circuit breakers supplying power to
Receiver Transmitter RT- 1241 to ON.
36. Set LOCAL TEST switch to ON and allow for 3
minute time delay.
37. Connect multimeter as indicated in Table 5-5
and verify correct dc voltage at each test point.
5-95
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