(3) Swing the assembly out of the way to
permit access to the bolometer mounting
block.
(4) Remove the block bottom half by
removing the three screws which hold it in
place (fig. 26). Unsolder and replace the
component.
b. Reassemble in reverse order.
71. Disassembly and Assembly of Modulation Switch
a. To remove an inaccessible part on the
MODULATION switch assembly (fig. 19), proceed as
follows:
(1) Remove the two 2-inch screws which
secure this assembly to the power chassis
Figure 28. Frequency range selector switch, interior
view.
(2) Remove the knob from S2 and the two
within one-eighth inch of coils L14, L17,
adjacent screws which hold the assembly
and L20 (fig. 25).
to the front panel.
(3) Turn the back stop screw into roughly
midpoint until it is certain that the
attenuator
cannot
become
disengaged.
69. Disassembly and Assembly of FREQ. RANGE-
MC Switch Cable
a. To remove the cable connected to the FREQ.
RANGE-.MC switch S5 (fig. 20), proceed as follows:
(1) Remove the knob and the nut which
secure the switch to the front panel
(2) Pull back switch S5 and remove the
(3) Loosen the setscrew securing the cable to
be replaced.(4) Unsolder the cable at the
switch S5 contact and pull the cable free.
b. To replace cable, reverse the above procedure.
70. Disassembly and Assembly of Bolometer
a. To remove RT3, RT4, R127, or R128 which are
as follows:
(1) Remove the three screws which secure J1
bolometer (fig. 29) mounting block to the
front panel.
(2) Remove the six screws which secure the
Figure 29. Bolometer assembly, interior view.
audio oscillator and deviation indicator
assembly TB2 to its mounting brackets
50
