6
Figure 4
Additional rolloff of the high frequency response will remove the raspy nature of the
receive audio, and this is accomplished by changing the value of capacitor C119 on the
I.F. board from 500pf to .001 µfd (Figure 3). The low-end audio response of the audio
amplifier increases slightly by replacing coupling capacitor C306 on the audio board with
a .01 µfd disk capacitor (Figure 2).
Any possibility of voltage regulator hash being generated by V18 is reduced by
connecting a .001 µfd 500V disk capacitor from V18 pin 1 to the ground foil on the audio
board.
Some of the ‘birdies’ and other internally-generated signals heard in the tuning range of
the receiver are reduced considerably by bypassing the filament string to ground with a
.01 µfd capacitor connected from the common filament point on the bandpass circuit
board to ground. This is the point where the four brown wires connect about an inch
below pin 1 of V19 (Figure 5).
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