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I MODEL 4OO TRANSCE]VER
B.
Installatiob (Cont)
C O N T R O L F U N C T ] O N S
Functions of the
O N . O F F
S W I T C H
FUNC TION
S W I T C H
Standby
Calib!ate
R e c e i v e
Transrnit
T une
Contlols the varioLls
m o d e s o f o p e r a t i o n o f
t h e t r a n 6 c e i v e r .
DC Supply - Power to the
t r a n s c e i v e r i s d i s a b l e d .
AC Supply - All voltages
except medium voltage
a r e s u P p l i e d .
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!
R 1 4 0 5 i n t h e b a l a n c e d
modulator
defl ection Plate
circuit,
and pe rmitg
b a l a n c i n g o f t h e c a r r i e r .
C o n t r o l s v a r i a b l e ! e s i s t o r
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
t h e s e s t a g e s .
Controls
potentiomete!
R l 2 0 l
i n g t i d c i r c u i t o I
v I 2 A F O u t p u t , a n d v a r i e s
the gain ot the final audio
output amplifie r,
C o n t r o l s C I 8 0 4 i n f r e q u e n c y
deterrnining
tank circuit
oI
!. !equency Control
Unit.
Controls
CIA and CIB in
plate tankE of transmitte!
Inix€!
and driver.
C o n t r o l s C 4 l ? i n p i - n e t w o r k
to tune linal power arnpli-
tier plate to resonance.
C o n t r o l s C 4 2 0 i n p i - n e t w o r k
to match impedance
of out-
put load.
TuneE input to
Receiver
RF Arnplifi€ r.
Switches in progres sively
m o r e c a p a c i t a n c e i n P a r a l -
lel with PA Load,
Fine.
Switche 6, plate coi1s, and
a s s o c i a t e d c a P a c i t o r s o f
V F O A m p l i f i e r ,
V I ,
T r a n 8 -
m i t t e r M i x e r ,
V 2 , a n d D r i -
v e r ,
V 3 ,
A l s o s w i t c h e s
tank coil of pi-coupling
s y s t e m a n d a s s o c i a t e d
capacitor s in PA outPut
l l
scleen voltage are aPPlied
AF GAIN
t o V l 3 , D C S u p p l y - 1 2
volts dc is provided
to the
relay ci !cuit,
high and
mediurn voltages supPlied
to the plate circuits
and
b i a s v o l t a g e i s p r o v i c e d
to the relay controlled
S a m e a 6 f o r C a l i b r a t e
b u t v o l t a S e t o V l 3
r e -
1 2 v o l t d c c i r c u i t t h r o u g h
relay Kl
and KZ i3 corn-
pleted,
and all tubes us€d
only in rec€ive
are
biased to cutoJf.
AII circuits
for transmit
a r e e n e r g i z e d , a s a b o v e ,
but only deflection
plate
of the balanced modula-
t o r i s g r o u n d e d , c a p a c i -
t o r C 1 5 0 4 i n t h e c a r r i e r
oscillator
ie removed
f r o r n g r o u n d , C 1 5 0 3 i s
grounded.
Control6
potentiometer
R 1 6 0 3 i n t h e g r i d V l 6 8
and controls
amount o{
audio to the balanced
modulato r.
PA TUNE
PA LOAD,
r.ine
PA LOAD,
C o a r s e
MAIN
BANDSWITCH
MICROPHONE
GAIN
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