Potentiometer R96 is located on the regulated B+
d. The B+ voltage regulator circuit in Facsim-
voltmeter M3 (fig. 65), which is also a component
ile Transceivers TT-1B/TXC-1 through TT-1F/
only of Facsimile Transceivers TT-1B/TXC-1,
TXC-1 (fig. 65) operates in the same manner as
through TT-1F/TXC-1. The value of R88 has
that described above. However, potentiometer
been modified so that it still provides minimum
R96 has been inserted into the grid circuit of
stabilization current for the reference voltage
stage V9 to permit easy control of the output
regulator tube V25.
voltage and to eliminate the necessity of shunting
R90 with R90A to obtain the correct voltage.
Figure 65. Control voltage amplifier, RB+ circuit, Facsimile Traneceivers TT-1B/TXC-1, TT-1C/TXC-1, TT-1D/TXC-1.
TT-1E/TXC-1, and TT-1F/TXC-1.
Section Ill. RECTIFIER POWER UNIT PP-86(*)/TXC-1
The rectifier power unit serves four purposes:
The high-voltage power supply rectifier (V22),
a. Provides unregulated B+ at 450 volts dc
located within Rectifier Power Unit PP-86(*)/
and filament voltage at 6.5 v ac for operation of
TXC-1, furnishes +450-volt unregulated dc for
the transceiver for a normal source of 115-volt
transceiver plate and screen circuits. The +450-
60-cycle ac.
volt, unregulated dc also is the source of voltage
b. Provides 115-volt 60-cycle ac for starting
for the voltage regulator (V7, V8, V9, and V25)
the synchronous motor in Facsimile Transceiver
located on the transceiver chassis (par. 80), which
TT-1(*)/TXC-1.
furnishes regulated +250 volts for critical trans-
c. Provides closely regulated voltage for the
ceiver circuits. Rectifier V22, type 5Z2, is con-
exciter lamp (6 volts at 1,800 cycles) from a 1,800-
nected in a conventional full-wave rectifier cir-
cycle signal supplied by the fork oscillator unit.
cuit. Transformer T11 changes the 115-volt ac
d. Rectifier Power Unit PP-86E/TXC-1 also
input on the primary side to high voltage for the
provides 115 volts at 60 cps for the dust removal
plates of V22, 5 volts for the filament of V22, 6.5
blower motor.
volts for filaments of other tubes in the power
