Figure 27. Typical attenuator core.
(4) Back off one nut and remove it and the
(4) Remove the seven screws which hold
washer that secure the potentiometer to
capacitor C36 in place (fig. 23) and
the mounting bracket.
remove the capacitor.
Note
(5) Remove the potentiometer.
Tube V8 (fig. 25) is not affected in the
b. To replace the potentiometer, proceed as
removal or replacement of C36.
follows:
b. To replace capacitor C36, proceed as follows:
(1) Secure the potentiometer to the mounting
bracket with one nut and washer.
(1) Position and secure the capacitor with
seven screws.
(2) Solder the leads and secure the
potentiometer mounting bracket to the
(2) Solder leads to C37, C38, and R57.
oscillator subplate with two screws.
(3) Position and replace RT2 and the
(3) Replace the rf assembly as described in
modulator chassis as outlined in
68. Disassembly and Assembly of Attenuators
(4) Replace tuning capacitor C16 as outlined
a. To remove any one of the three attenuators
Note
(1) Remove the six screws which secure the
In replacing any tuning capacitor,
audio oscillator and deviation indicator
preload the spring (fig. 24) in the split
terminal board TB2 (fig. 20) to its
gears two and one-half teeth before
mounting brackets.
meshing with the main shaft gears.
Gears should mesh as closely as
(2) Tilt this assembly out of the way; be
possible without binding. Adjust all
careful not to damage the wiring harness.
rotors so that the plates are fully
(3) On the front panel (fig. 5), turn the
meshed simultaneously.
OUTPUT knob to back the attenuators out
67. Disassembly and Assembly of Potentiometer
until a limit stop is reached.
R65 and R66
(4) Back off the front stop screw and the back
stop screw, and back out the attenuator
and 22), proceed as follows:
(1) Remove the rf assembly as described in
b. To replace the attenuators, proceed as follows:
(1) Slide the attenuators into their respective
(2) Remove the two screws which secure the
positions (fig. 26).
potentiometer mounting bracket to the
(2) Turn the front stop screw to roughly
oscillator subplate (fig. 22).
midpoint. Adjust the front stop screw and
(3) Unsolder the leads and remove the
slip the gears on the attenuators until the
potentiometer mounting bracket (fig. 22).
attenuator pick-up coils approach
49
