ALC CIRCUIT
The 28 MHz input signal from the transceiver is fed
to the ALC AMP unit, where it is amplified by
Qisoi
(3SK59Y ).
Gate 1 receives the RF signal,
while gate 2 is
.
connected to the ALC voltage
supplied from the various modules. The ALC
voltage is used to control the gain of Qisoi. In the
AM mode, the ALC level is fixed, and no
connection is made to the modules for the
individulal bands.
A portion of the input signal is detected by Di soi
and Diso2
(1S1555),
for an indication of the input
level on the meter.
SWITCHING CIRCUITS
(1) POWE R switch O F F
Heater voltage from the transceiver appears at the
ACC connector, when proper connections are
made to the FTV-901 R. When the transceiver
heater switch is ON, and the FTV-901R power
switch is OFF, RLi is set to OFF, and the 10 m
OUT jack is connected to the HF ANT jack, per
mitting normal HF operation. After the transverter
is turned off, a warmup time of approximately 1
minute is required to allow the transceiver tubes to
reach operating temperature.
(2) POWE R switch ON
When the FTV-901R is turned on, voltage is
applied to relay driver Qi7 03
(2SC1815Y)
turning
it on. With the conduction of Qi 7 03 , RLi is
REG
UNIT
(PB-1945)
F
1102
MUL Tl JACK
activated, connecting the 10 meter output to the
various units of the transverter, according to the
position of the bandswitch. When the heater switch
is on, and the FTV-901 R is not in use, RLi 9 0 i
switches the external receiver to the HF antenna
on receive.
When the heater switch is turned off, Qi 9 02
(2SC1815Y)
is switched on, switching the EXT
RCV jack to be in parallel with the HF ANT jack,
allowing monitoring on the external receiver. If
the external receiver is not normaily used for
monitoring, the heater switch should always be
left on.
POWE R SUPPLY
The AC voltage from the power transformer is
rectified by bridge rectifier, and stabilized at
13.8 volts by Qi 7 07
(MJE3055),
Qi 7 oi
(2SD235),
and Qi 7 02
(TA 7089M).
This voltage is used for the
LE D UNIT, pilot lamps, and the three converter
units.
Di7 o6
(WZllO)
provides 11 volts for the local
oscillator
diode switch circuits, while Qi 7 06
(µPC14308)
regulates the 13.8 volt line from
RLi 7 oi for the low voltage circuits.
On the VR UNIT, diode switches Di9 oi - Di9i2
(1S1555)
select voltage regulating potentimeters
VR i 9 o i -VR i 9 i 2 , for tuning the varactor-diode
tuned circuits in the various units.
VR
UNIT(
PB-1947)
......
.....
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