TM 11-5820-890-20-1
1.9.
DC POWER INPUT AND DISTRIBUTION. Continued
f.
Power Supply Module. The 22 to 32 V dc is applied to power supply Al. This power supply is a
dc-to-dc converter which takes the 22 to 32 V dc and produces the following voltages:
6.5 to
7.25 V dc
12.6 to
13.4 Vdc
180.0 to 220.0 V dc
These voltages are used by RT-A, RT-B, RCU-A, RCU-8, control-monitor, and power amplifier
installed on the VAA.
9
Power Distribution in Power Amplifier Mount (PA mount) MT-6353. The 22 to 32 V dc enters the PA
mount through J1, pin B from J2, pin B of the MB. The 22 to 32 V dc used to energize the K1 relay
enters the PA mount through J1, pin C from J2, pin C of the MB. When CB1 of the VAA is set to ON, 22
to 32 V dc will be applied to J1, pin C of the PA mount causing the K1 relay to energize. This allows the
22 to 32 V dc at J1, pin B to be applied to power supply Al of the PA mount when CB1 is set to ON.
This, in turn, allows DS1 to light.
h.
Power Distribution in the Loudspeaker-Control Unit LS-671. The loudspeaker-control unit LS-671
controls the power to the radio with its ON/OFF switch if the VAA is set to REMOTE.
The primary power enters the MB at connector J1, pin B. From here it is distributed to connectors J3
and J4, pin B. A loudspeaker cable carries the dc to the LS-671 system connector J1, pin B. If the
loudspeaker ON/OFF switch is in the ON position, the dc power from pin B is connected to pin D. The
loudspeaker cable carries the dc back to the MB connectors J3 and J4, pin D. Pin D of the MB is
connected to the MB system connector J5, pin E. This is a direct connection to VAA system connector
P1, pin E.
DC power on P1, pin E of the VAA energizes relay K1 allowing dc power to exit on pin C. Pin C of the MB
distributes the dc power to connectors J3 and J4. The loudspeaker cable carries the dc through LS-671
system connector J1, pin C, to power the audio amplifier.
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