Swann 400 - Page 12

I
MODEL
4OO TRANSCE]VER
B. Installatiob
(Cont)
CONTROL
FUNCT]ONS
Functions
of the
ON.OFF
SWITCH
FUNC TION
SWITCH
Standby
Calib!ate
Rec eive
Transrnit
T une
Contlols
the varioLls
modes
of operation
of
the tran6ceiver.
DC
Supply
-
Power
to the
transceiver
is disabled.
AC
Supply
-
All voltages
except medium
voltage
are
suPplied.
AC
Supply
-
Plate
and
RF CAIN
(In
F
requency
Control
Unit)
MAIN
TUNING
PA GRID
various
contlols
are as
follows:
Controls
main
po\rer
to
CARRIER
the transceive
!.
BALANCE
Controls
potentiohete!
R1405
in the
balanced
modulator
defl
ection
Plate
circuit, and
pe rmitg
balancing
of the carrier.
Controls
variable
!esistor
Rl80l
which
is cornrnon
itr
the
cathodes
of
V6,
RF
AmpliJie
!, V8
l st IF Am
-
plifier and V9,
znd IF
Am-
plifier, controlling
gain
of
these
stages.
Controls
potentiomete!
Rl20l
in gtid circuit
oI
vI2 AF
Output, and
varies
the
gain ot the final
audio
output amplifie
r,
Controls C
I804 in frequency
deterrnining
tank circuit
oI
!. !equency
Control
Unit.
Controls
CIA and CIB
in
plate tankE
of transmitte!
Inix€! and driver.
Controls
C4l
? in pi-network
to tune
linal
power
arnpli-
tier
plate to
resonance.
Controls
C420 in
pi
-network
to match
impedance
of out-
put
load.
TuneE input
to
Receiver
RF
Arnplifi€ r.
Switches
in
progres
sively
more
capacitance
in
Paral-
lel with
PA Load, Fine.
Switche
6,
plate coi1s, and
associated
caPacitors
of
VFO
Amplifier, VI,
Tran8
-
mitter Mixer,
V2,
and Dri-
ver,
V3,
Also switches
tank
coil of
pi-coupling
system and
associated
capacitor
s in PA
outPut
ll
scleen
voltage are
aPPlied
AF
GAIN
to Vl3,
DC
Supply
-
12
volts dc
is
provided
to
the
relay ci !cuit,
high and
mediurn
voltages supPlied
to
the
plate
circuits
and
bias voltage is
proviced
to
the relay controlled
Same
a6 for Calibrate
but voltaSe
to Vl3
re-
12 volt
dc circuit
through
relay Kl and
KZ i3 corn-
pleted, and all tubes
us€d
only
in rec€ive are
biased
to cutoJf.
AII circuits for
transmit
are
energized, as above,
but only deflection
plate
of the
balanced modula-
tor is
grounded, capaci
-
tor C1504 in the
carrier
oscillator
ie removed
frorn ground, C 1503
is
grounded.
Control6
potentiometer
R1603
in the
grid
Vl68
and controls
amount o{
audio to the balanced
modulato
r.
PA TUNE
PA
LOAD,
r.ine
PA LOAD,
Coarse
MAIN
BANDSWITCH
MICROPHONE
GAIN