Western Electric 407A-4, Instruction Manual

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The letters ass igned to the units and assembl ies of
apparatus are :
Unit A - D-99110 Oscillator - Amplifier
Unit C - D-151135 Modulating Amplifier
Units D and E - D..;9 9118 Power .Amplifier
Unit F - Special D-99116 Contro l Unit
Unit G - Special D- 99114 Rectifier Unit
Unit H - D-9911 9 Rectifier Tube Unit
Unit J - .Antenna-Coupl ing Unit
Unit
K
- D-99120 B ias Rectifier
Unit N - Nitrogen Gas System
Unit P - Power Apparatus
Unit W - Water System
Main Transmitter
The five transmitter units in the ma.in panel assembly
are in the form of metal cabinets with doors in front pro­
viding access to the interior . The contents of the indivi d­
ual units are briefly summarized below :
D-99110 This unit con­
tains two 702A Oscillators, the three-stage radi o-frequency
amplifier, the three-stage audio-frequency amplifier, the
plate-supply rectifier and control apparatus for these
amplifiers, and feedback and monitoring rectifiers .
D- 151135 Two 232B
water-cooled tubes are mounted in this unit together with
their input and output circuits, tuning controls , individ­
ual filament regulator s , and insulating water piping.
D-9911 8 Power
D and
The two units
constituting the high-efficiency 50-kilowatt stage contain
the two 298A water-cooled tubes complete with their input
and shielded output circuits , tuning control s , individual
filament regulators , and a harmoni c fi lter. The coaxial.
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