Section IV
Paragraphs 4-70 to 4-78
the power supplies which use the +230-volt unregu-
h. 90~. 90 cps from the LOC-GS attenuator is fed
lated output and three +150-volt regulated outputs
to S1402B and all other audio circuits are disabled.
from voltage regulator V1410, V1411 and V1412.
These B+ voltages are used throughout the signal
i. 150~. 150 cps from LOC-GS attenuator is fed to
generator.
S1402B and all other audio circuits are disabled.
4-75. POWER INPUT AND DYNAMOTOR CIRCUIT.
4-71. METER CIRCUIT.
(See figure 4-27.)
(See figure 4-25.)
4-76. Power Cord CX-1095/U connects 21 to 29 volts
4-72. Meter M1401 is provided on the front panel for
dc to the input receptacle J1402. Fuses F1401 and
measuring the unregulated B+ voltage, the adjusted
line voltage (dynamotor input) and the carrier level.
F 1402 protect both input lines. The tnput power is
The meter has a 0 to 200 microampere movement and
fed to SET LINE TO 21V control S1404 whose con-
with METER switch S1403 in the LINE and B+ posi-
tacts connect 0.2-ohm resistors in series with the
tions it is converted to a 0 to 30 volt d-c voltmeter by
input line as required to reduce the input voltage to
adding multiplier resistor R1482 in series with it.
21 volts. When turned fully counterclockwise to OFF,
With S1403 in the B+ position, voltage divider R1476
S1404 disconnects all power from the signal genera-
and R1477 provides a 10 to 1 reduction in the unregu-
tor. The output of the line voltage control is fed to
lated B+ voltage so that it can be measured by the 0 to
pilot lamp I1401 for power-on indication, to the signal
30 volt voltmeter. In the CAR position, the meter is
generator filament circuits, to the meter circuit for
connected to the demodulated output of the r-f chassis
measurement, and through input filter C1407 and
and to METER ZERO control R1480 which is used to
L1402 to dynamotor D1401. The dynamotor is a d-c
zero the meter when no r-f signal is applied to de-
motor operating on 21 volts with a common rotor that
modulator V1509 in the r-f chassis. AUDIO OUT jack
generates 260 volts. Capacitors C1411 and C1410
J1408 provides a convenient test point for checking
across the dynamotor brushes reduce arcing at the
the audio signals.
commutators. The 260-volt dynamotor output is fil-
tered by L1403 and C1408A and fed to the power
4-73. POWER SUPPLY.
supplies.
4-74. INTRODUCTION. The power supply (figure
4-77. POWER SUPPLIES.
(See figure 4-28.)
from the power source and supplies 21 volts dc for the
signal generator tube filaments and +230 volts unreg-
ulated and +150 volts regulated for B+ voltages. 21 to
through RC filter R1428 and C1407C which drops the
29 volts dc from the power source is fed through the
voltage to 230 volts for use by V1406A and the r-f
line voltage control which allows setting the input volt-
chassis as B+ voltage. 230 volts is also fed through
age to 21 volts. The 21-volt output is fed to dyna-
NAV-GS switch S1406 to the univerter chassis. When
motor D1401 and supplies filament power to the audio,
in NAV operation, the univerter chassis is not re-
univerter and r-f chassis. The dynamotor output feeds
quired and S1406 disconnects its B+ supply. The
