TM 11-5840-360-14-1-1
4. Disconnect all wires from the local oscillator
3. Remove Power Module Assembly A1200 per
assembly, noting and tagging the connection locations.
5. Remove the four nuts attaching the oscillator to
4. Disconnect all wires from the A1600 assembly,
the IF Amplifier Assembly and remove the oscillator
tagging each for connection point.
assembly.
5. Disconnect BNC plug at A1600 J1.
6. Reinstall using the reverse of the above.
6. Remove screw, lockwasher and flat washer
which secure right-hand side of A1600 assembly to
5.10.2.5 Mixer Diodes CR5/CR6. - See Figure 5-1; refer
chassis mounting bracket.
to assembly drawings in Chapter 6, Section 6.2 as
7. Remove the four nuts and lockwashers which
necessary.
secure the 900 E-bend waveguide flange to the
1. Insure removal of power from the unit per
waveguide tee on the A1600 assembly; withdraw the
A1600 assembly from the unit.
2. Unscrew one of the mixer diodes caps and note
8. Replace IF Amplifier and Mixer Assembly
the polarity of the diode installed.
A1600 using the reverse of the above.
CAUTION
5.10.2.8 Power Module Assembly A1200. - See Figure
A. DO NOT EXPOSE MIXER DIODES
TO EXCESSIVE RF RADIATION.
as necessary.
B. IF MIXER DIODE FORWARD/
1. Insure removal of power from the unit per
REVERSE RATIO IS TO BE
CHECKED, DO NOT USE THE RX
2. Remove front cover; loosen control panel
10,000 FUNCTION OF THE
captive screws and swing control panel into its service
position.
3. Remove the seven screws and lockwashers that
attach the Power Module to the center bracket of the
3. If replacement is necessary, install the new
Receiver Transmitter chassis.
diode in the cap in the same polarity as the original
diode, and screw cap into mixer assembly.
4. Lift the Power Module up and out far enough to
access the harness connector.
4. Repeat steps 2 and 3 for second mixer diode.
5. Disconnect the harness connector and remove
5.10.2.6 Relay Kl1. - See Figure 5-1; refer to assembly
the Power Module from the unit.
drawing in Chapter 6, Section 6.2 as necessary.
6. Replace the Power Module Assembly A1200
1. Insure removal of power from the unit per
using the reverse of the above.
2. Remove front cover; loosen control panel
5.10.3 Alignment Procedures
captive screws and swing control panel into its service
position.
When performed in the sequence indicated, the
instructions given in paragraphs 5.10.3.1 through
3. Remove the hardware that secures the terminal
board bracket; relay K1 is located on the back side of
procedure for Receiver Transmitter RT-1240. The
the bracket.
functions covered in each of the procedures should be
4. Pull the bracket forward just enough to gain
checked and adjusted as necessary following all repair
access to the two screws holding the relay.
or replacement activities.
5. Disconnect all wires from the relay terminals,
tagging each for connection point.
NOTE:
6. Remove the two screws which hold the relay
For V2, V3 or V4 systems, observe
and withdraw the relay.
Switching Unit setting and refer to
7. Replace relay K1 using the reverse of the
above.
determine which Indicator is serving
as the master for the Receiver
5.10.2.7 IF Amplifier and Mixer Assembly A1600. See
Transmitter under test.
Section 6.2 as necessary.
5.10.3.1 Power Module Frequency Adjustment.
-
1. Insure removal of power from the unit per
Perform the following steps to check operating
frequency of power module:
2. Remove front cover; loosen control panel
1. Set master Indicator POWER switch to ST BY.
captive screws and swing control panel into its service
position.
5-20
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